<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncome" xlink:href="colb-20181231.xsd#AccumulatedOtherComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeAmountsReclassifiedFromAccumulatedOtherComprehensiveIncomeDetails" xlink:href="colb-20181231.xsd#AccumulatedOtherComprehensiveIncomeAmountsReclassifiedFromAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeDetails" xlink:href="colb-20181231.xsd#AccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeTables" xlink:href="colb-20181231.xsd#AccumulatedOtherComprehensiveIncomeTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCredit" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCredit" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAllowanceForNoncoveredLoanAndLeaseLossesDetails" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAllowanceForNoncoveredLoanAndLeaseLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAnalysisOfCreditQualityOfLoanPortfolioDetails" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAnalysisOfCreditQualityOfLoanPortfolioDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditChangesInAllowanceForUnfundedCommitmentsAndLettersOfCreditDetails" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditChangesInAllowanceForUnfundedCommitmentsAndLettersOfCreditDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditNarrativeDetails" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditTables" xlink:href="colb-20181231.xsd#AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/BusinessCombinations" xlink:href="colb-20181231.xsd#BusinessCombinations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/BusinessCombinationsDetails" xlink:href="colb-20181231.xsd#BusinessCombinationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/BusinessCombinationsNarrativeDetails" xlink:href="colb-20181231.xsd#BusinessCombinationsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/BusinessCombinationsTables" xlink:href="colb-20181231.xsd#BusinessCombinationsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/CashAndCashEquivalents" xlink:href="colb-20181231.xsd#CashAndCashEquivalents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/CashAndCashEquivalentsDetails" xlink:href="colb-20181231.xsd#CashAndCashEquivalentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilities" xlink:href="colb-20181231.xsd#CommitmentsAndContingentLiabilities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilitiesDetails" xlink:href="colb-20181231.xsd#CommitmentsAndContingentLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilitiesTables" xlink:href="colb-20181231.xsd#CommitmentsAndContingentLiabilitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedBalanceSheets" xlink:href="colb-20181231.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="colb-20181231.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="colb-20181231.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:href="colb-20181231.xsd#ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="colb-20181231.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:href="colb-20181231.xsd#ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ConsolidatedStatementsOfIncome" xlink:href="colb-20181231.xsd#ConsolidatedStatementsOfIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/Deposits" xlink:href="colb-20181231.xsd#Deposits" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DepositsDetails" xlink:href="colb-20181231.xsd#DepositsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DepositsTables" xlink:href="colb-20181231.xsd#DepositsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsetting" xlink:href="colb-20181231.xsd#DerivativesAndBalanceSheetOffsetting" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingBalanceSheetOffsettingDetails" xlink:href="colb-20181231.xsd#DerivativesAndBalanceSheetOffsettingBalanceSheetOffsettingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingDetails" xlink:href="colb-20181231.xsd#DerivativesAndBalanceSheetOffsettingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingTables" xlink:href="colb-20181231.xsd#DerivativesAndBalanceSheetOffsettingTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/DocumentAndEntityInformation" xlink:href="colb-20181231.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EarningsPerCommonShare" xlink:href="colb-20181231.xsd#EarningsPerCommonShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EarningsPerCommonShareScheduleOfBasicAndDilutedEarningsPerShareDetails" xlink:href="colb-20181231.xsd#EarningsPerCommonShareScheduleOfBasicAndDilutedEarningsPerShareDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EarningsPerCommonShareTables" xlink:href="colb-20181231.xsd#EarningsPerCommonShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EmployeeBenefitPlans" xlink:href="colb-20181231.xsd#EmployeeBenefitPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EmployeeBenefitPlansDetails" xlink:href="colb-20181231.xsd#EmployeeBenefitPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/EmployeeBenefitPlansTables" xlink:href="colb-20181231.xsd#EmployeeBenefitPlansTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurement" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurement" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementCarryingAmountsAndEstimatedFairValuesOfSelectedFinancialInstrumentsDetails" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurementCarryingAmountsAndEstimatedFairValuesOfSelectedFinancialInstrumentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementFinancialAssetsAccountedForFairValueOnNonrecurringBasisDetails" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurementFinancialAssetsAccountedForFairValueOnNonrecurringBasisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementFinancialAssetsAndLiabilitiesAccountedForFairValueOnRecurringBasisDetails" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurementFinancialAssetsAndLiabilitiesAccountedForFairValueOnRecurringBasisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementQuantitativeInformationAboutLevel3FairValueMeasurementsDetails" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurementQuantitativeInformationAboutLevel3FairValueMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementTables" xlink:href="colb-20181231.xsd#FairValueAccountingAndMeasurementTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowings" xlink:href="colb-20181231.xsd#FederalHomeLoanBankAndFederalReserveBankBorrowings" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowingsDetails" xlink:href="colb-20181231.xsd#FederalHomeLoanBankAndFederalReserveBankBorrowingsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowingsTables" xlink:href="colb-20181231.xsd#FederalHomeLoanBankAndFederalReserveBankBorrowingsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/GoodwillAndIntangibleAssets" xlink:href="colb-20181231.xsd#GoodwillAndIntangibleAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:href="colb-20181231.xsd#GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsSummaryOfEstimatedFutureAmortizationExpenseOfCoreDepositIntangiblesDetails" xlink:href="colb-20181231.xsd#GoodwillAndIntangibleAssetsSummaryOfEstimatedFutureAmortizationExpenseOfCoreDepositIntangiblesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsTables" xlink:href="colb-20181231.xsd#GoodwillAndIntangibleAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/IncomeTax" xlink:href="colb-20181231.xsd#IncomeTax" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/IncomeTaxDetails" xlink:href="colb-20181231.xsd#IncomeTaxDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/IncomeTaxTables" xlink:href="colb-20181231.xsd#IncomeTaxTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/JuniorSubordinatedDebt" xlink:href="colb-20181231.xsd#JuniorSubordinatedDebt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/JuniorSubordinatedDebtDetails" xlink:href="colb-20181231.xsd#JuniorSubordinatedDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/JuniorSubordinatedDebtTables" xlink:href="colb-20181231.xsd#JuniorSubordinatedDebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/Loans" xlink:href="colb-20181231.xsd#Loans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansAnalysisOfAgedLoanPortfolioDetails" xlink:href="colb-20181231.xsd#LoansAnalysisOfAgedLoanPortfolioDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansAnalysisOfImpairedLoansDetails" xlink:href="colb-20181231.xsd#LoansAnalysisOfImpairedLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansAnalysisOfLoanPortfolioByMajorTypesOfLoansDetails" xlink:href="colb-20181231.xsd#LoansAnalysisOfLoanPortfolioByMajorTypesOfLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansAnalysisOfNonaccrualLoansDetails" xlink:href="colb-20181231.xsd#LoansAnalysisOfNonaccrualLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansLoansAnalysisOfPurchasedCreditImpairedAccretableYieldRollforwardDetails" xlink:href="colb-20181231.xsd#LoansLoansAnalysisOfPurchasedCreditImpairedAccretableYieldRollforwardDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansLoansAnalysisOfPurchasedCreditImpairedLoansDetails" xlink:href="colb-20181231.xsd#LoansLoansAnalysisOfPurchasedCreditImpairedLoansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansLoansAnalysisOfTroubledDebtRestructuringsDetails" xlink:href="colb-20181231.xsd#LoansLoansAnalysisOfTroubledDebtRestructuringsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansNarrativeDetails" xlink:href="colb-20181231.xsd#LoansNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/LoansTables" xlink:href="colb-20181231.xsd#LoansTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/OtherRealEstateOwned" xlink:href="colb-20181231.xsd#OtherRealEstateOwned" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/OtherRealEstateOwnedSummaryOfOtherRealEstateOwnedDetails" xlink:href="colb-20181231.xsd#OtherRealEstateOwnedSummaryOfOtherRealEstateOwnedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/OtherRealEstateOwnedTables" xlink:href="colb-20181231.xsd#OtherRealEstateOwnedTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ParentCompanyFinancialInformation" xlink:href="colb-20181231.xsd#ParentCompanyFinancialInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedBalanceSheetsDetails" xlink:href="colb-20181231.xsd#ParentCompanyFinancialInformationCondensedBalanceSheetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedStatementsOfCashFlowsDetails" xlink:href="colb-20181231.xsd#ParentCompanyFinancialInformationCondensedStatementsOfCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedStatementsOfIncomeDetails" xlink:href="colb-20181231.xsd#ParentCompanyFinancialInformationCondensedStatementsOfIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ParentCompanyFinancialInformationTables" xlink:href="colb-20181231.xsd#ParentCompanyFinancialInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/PremisesAndEquipment" xlink:href="colb-20181231.xsd#PremisesAndEquipment" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/PremisesAndEquipmentDetails" xlink:href="colb-20181231.xsd#PremisesAndEquipmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/PremisesAndEquipmentTables" xlink:href="colb-20181231.xsd#PremisesAndEquipmentTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RegulatoryCapitalRequirements" xlink:href="colb-20181231.xsd#RegulatoryCapitalRequirements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RegulatoryCapitalRequirementsDetails" xlink:href="colb-20181231.xsd#RegulatoryCapitalRequirementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RegulatoryCapitalRequirementsTables" xlink:href="colb-20181231.xsd#RegulatoryCapitalRequirementsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RevenueFromContractsWithCustomers" xlink:href="colb-20181231.xsd#RevenueFromContractsWithCustomers" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RevenueFromContractsWithCustomersDetails" xlink:href="colb-20181231.xsd#RevenueFromContractsWithCustomersDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/RevenueFromContractsWithCustomersTables" xlink:href="colb-20181231.xsd#RevenueFromContractsWithCustomersTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/Securities" xlink:href="colb-20181231.xsd#Securities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesCarryingValueOfSecuritiesPledgedAsCollateralDetails" xlink:href="colb-20181231.xsd#SecuritiesCarryingValueOfSecuritiesPledgedAsCollateralDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesNarrativeDetails" xlink:href="colb-20181231.xsd#SecuritiesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesScheduleOfContractualMaturitiesOfInvestmentSecuritiesAvailableForSaleDetails" xlink:href="colb-20181231.xsd#SecuritiesScheduleOfContractualMaturitiesOfInvestmentSecuritiesAvailableForSaleDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSecuritiesAvailableForSaleDetails" xlink:href="colb-20181231.xsd#SecuritiesSecuritiesAvailableForSaleDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSecuritiesSummaryOfGrossRealizedGainsAndLossesDetails" xlink:href="colb-20181231.xsd#SecuritiesSecuritiesSummaryOfGrossRealizedGainsAndLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchase" xlink:href="colb-20181231.xsd#SecuritiesSoldUnderAgreementsToRepurchase" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchaseDetails" xlink:href="colb-20181231.xsd#SecuritiesSoldUnderAgreementsToRepurchaseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchaseTables" xlink:href="colb-20181231.xsd#SecuritiesSoldUnderAgreementsToRepurchaseTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesSummaryOfGrossUnrealizedLossesAndFairValueOfInvestmentsWithUnrealizedLossesDetails" xlink:href="colb-20181231.xsd#SecuritiesSummaryOfGrossUnrealizedLossesAndFairValueOfInvestmentsWithUnrealizedLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SecuritiesTables" xlink:href="colb-20181231.xsd#SecuritiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareBasedPayments" xlink:href="colb-20181231.xsd#ShareBasedPayments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareBasedPaymentsShareAwardsDetails" xlink:href="colb-20181231.xsd#ShareBasedPaymentsShareAwardsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareBasedPaymentsShareOptionsDetails" xlink:href="colb-20181231.xsd#ShareBasedPaymentsShareOptionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareBasedPaymentsTables" xlink:href="colb-20181231.xsd#ShareBasedPaymentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareholdersEquity" xlink:href="colb-20181231.xsd#ShareholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareholdersEquityDetails" xlink:href="colb-20181231.xsd#ShareholdersEquityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/ShareholdersEquityDividendsDeclaredTables" xlink:href="colb-20181231.xsd#ShareholdersEquityDividendsDeclaredTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubordinatedDebentures" xlink:href="colb-20181231.xsd#SubordinatedDebentures" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubordinatedDebenturesDetails" xlink:href="colb-20181231.xsd#SubordinatedDebenturesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubordinatedDebenturesTables" xlink:href="colb-20181231.xsd#SubordinatedDebenturesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubsequentEvents" xlink:href="colb-20181231.xsd#SubsequentEvents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubsequentEventsDetails" xlink:href="colb-20181231.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SubsequentEventsTables" xlink:href="colb-20181231.xsd#SubsequentEventsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnaudited" xlink:href="colb-20181231.xsd#SummaryOfQuarterlyFinancialInformationUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnauditedDetails" xlink:href="colb-20181231.xsd#SummaryOfQuarterlyFinancialInformationUnauditedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnauditedTables" xlink:href="colb-20181231.xsd#SummaryOfQuarterlyFinancialInformationUnauditedTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="colb-20181231.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="colb-20181231.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="colb-20181231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeAmountsReclassifiedFromAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2A4E26DD164E1EFFA76F0803BDB75E50" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2A4E26DD164E1EFFA76F0803BDB75E50" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_28F3C7DFFF288D8673610803BDC743E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2A4E26DD164E1EFFA76F0803BDB75E50" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_28F3C7DFFF288D8673610803BDC743E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_BECC2D383F62A810211B0803BDC70A8B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_28F3C7DFFF288D8673610803BDC743E0" xlink:to="loc_us-gaap_TypeOfAdoptionMember_BECC2D383F62A810211B0803BDC70A8B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_BECC2D383F62A810211B0803BDC70A8B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_28F3C7DFFF288D8673610803BDC743E0" xlink:to="loc_us-gaap_TypeOfAdoptionMember_BECC2D383F62A810211B0803BDC70A8B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingStandardsUpdate201802Member" xlink:label="loc_colb_AccountingStandardsUpdate201802Member_794863DF85C7B1751F620803BDC7E8F1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_BECC2D383F62A810211B0803BDC70A8B" xlink:to="loc_colb_AccountingStandardsUpdate201802Member_794863DF85C7B1751F620803BDC7E8F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_4A402C6C649B0F84855A0803BDC7CFD6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2A4E26DD164E1EFFA76F0803BDB75E50" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_4A402C6C649B0F84855A0803BDC7CFD6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_FEE3771E3723B92355340803BDC7C2B4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_4A402C6C649B0F84855A0803BDC7CFD6" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_FEE3771E3723B92355340803BDC7C2B4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_FEE3771E3723B92355340803BDC7C2B4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_4A402C6C649B0F84855A0803BDC7CFD6" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_FEE3771E3723B92355340803BDC7C2B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_C2CD1C15A03297382CEC0803BDC75514" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_FEE3771E3723B92355340803BDC7C2B4" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_C2CD1C15A03297382CEC0803BDC75514" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_42117227585286FE1A1D0803BDC72AC8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2A4E26DD164E1EFFA76F0803BDB75E50" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_42117227585286FE1A1D0803BDC72AC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_42117227585286FE1A1D0803BDC72AC8" xlink:to="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_42117227585286FE1A1D0803BDC72AC8" xlink:to="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_05E64D4F0740A5637DA50803BDC756CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_05E64D4F0740A5637DA50803BDC756CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_33BE6EF20057E072F5300803BDC7F91D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_33BE6EF20057E072F5300803BDC7F91D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_DA1A941F7AA925ADA36B0803BDC73548" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ABC7E97310613F40EE3E0803BDC7A482" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_DA1A941F7AA925ADA36B0803BDC73548" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_F4384B42C71EE63F3F700803BDC77352" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_F4384B42C71EE63F3F700803BDC77352" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_8CDF9E1333CC528BB7C20803BDC7DBCD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_8CDF9E1333CC528BB7C20803BDC7DBCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_E00F4D73BECBF19AA5D10803BDC7B01D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_E00F4D73BECBF19AA5D10803BDC7B01D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_598A498A57B934DCAADD0803BDC78578" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_598A498A57B934DCAADD0803BDC78578" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_EB0C1D3010033777BF1E0803BDC7420C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_NetIncomeLoss_EB0C1D3010033777BF1E0803BDC7420C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="loc_us-gaap_LaborAndRelatedExpense_92ED2A6B09F19EFD35700803BDC7A077" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_8CA1C892D0DC1FEB39FA0803BDC7BC2C" xlink:to="loc_us-gaap_LaborAndRelatedExpense_92ED2A6B09F19EFD35700803BDC7A077" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5AB54BE1DF246A74054E3E636BC00729" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5AB54BE1DF246A74054E3E636BC00729" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_EEE5D822D8F298A2C7643E636BC06D0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5AB54BE1DF246A74054E3E636BC00729" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_EEE5D822D8F298A2C7643E636BC06D0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_EEE5D822D8F298A2C7643E636BC06D0F" xlink:to="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_EEE5D822D8F298A2C7643E636BC06D0F" xlink:to="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201601Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201601Member_54CEB6EDA812858799013E636BC049E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF" xlink:to="loc_us-gaap_AccountingStandardsUpdate201601Member_54CEB6EDA812858799013E636BC049E8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingStandardsUpdate201802Member" xlink:label="loc_colb_AccountingStandardsUpdate201802Member_5149746F34D2D22F64053E636BC026F4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_6CC8C6B7B3D9F3AA104B3E636BC02EDF" xlink:to="loc_colb_AccountingStandardsUpdate201802Member_5149746F34D2D22F64053E636BC026F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4F3423FEDC0BCD9E256C3E636BC0DC88" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5AB54BE1DF246A74054E3E636BC00729" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4F3423FEDC0BCD9E256C3E636BC0DC88" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4F3423FEDC0BCD9E256C3E636BC0DC88" xlink:to="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4F3423FEDC0BCD9E256C3E636BC0DC88" xlink:to="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_BD8F67EDE1AED8A178723E636BC071DE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_BD8F67EDE1AED8A178723E636BC071DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_9C77015608AF4CE40B273E636BC02ECF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_9C77015608AF4CE40B273E636BC02ECF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_4C4930BFF249786BC0943E636BC0FAA4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F996A9C5544EE45265AE3E636BC06C2D" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_4C4930BFF249786BC0943E636BC0FAA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_3FB47DD5B8B5DF20E8533E636BC0D66A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_3FB47DD5B8B5DF20E8533E636BC0D66A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_E6301686EEF3A0700F573E636BC013C4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_E6301686EEF3A0700F573E636BC013C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_B5D2777414E4B60CAD823E636BC056AC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_B5D2777414E4B60CAD823E636BC056AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_9BFE9D5BE7E4BB3A80AC3E636BC012C6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_9BFE9D5BE7E4BB3A80AC3E636BC012C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_26F09E5DE9C09508D7813E636BC0A2E5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_784457CECED9B7F41EEA3E636BC08CFB" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_26F09E5DE9C09508D7813E636BC0A2E5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AccumulatedOtherComprehensiveIncomeTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCredit" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAllowanceForNoncoveredLoanAndLeaseLossesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_70698D018F4D9039DD495B4F0A9878D8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_D7490E3A7E9CDE9E6A455B4F0A981D2D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_70698D018F4D9039DD495B4F0A9878D8" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_D7490E3A7E9CDE9E6A455B4F0A981D2D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_597804C818315B6F112F5B4F0A98B08D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_D7490E3A7E9CDE9E6A455B4F0A981D2D" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_597804C818315B6F112F5B4F0A98B08D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_597804C818315B6F112F5B4F0A98B08D" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_597804C818315B6F112F5B4F0A98B08D" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_9AB9CDA02990DA5972C65B4F0A9848FC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_9AB9CDA02990DA5972C65B4F0A9848FC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_0DE3E8302DAC3D2EC1A35B4F0A98312B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_0DE3E8302DAC3D2EC1A35B4F0A98312B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_FCF41FE69168F884A8E55B4F0A98EA57" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_FCF41FE69168F884A8E55B4F0A98EA57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_75C972FE729C24B2984B5B4F0A988C55" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_75C972FE729C24B2984B5B4F0A988C55" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_87147CACC66509E9FA075B4F0A9864D0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_87147CACC66509E9FA075B4F0A9864D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UnallocatedFinancingReceivablesMember" xlink:label="loc_us-gaap_UnallocatedFinancingReceivablesMember_1820ACB994D334AE03425B4F0A981595" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_us-gaap_UnallocatedFinancingReceivablesMember_1820ACB994D334AE03425B4F0A981595" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_5B56A2E051A0A34D25F25B4F0A980EC3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_SecuredLoansMember_5B56A2E051A0A34D25F25B4F0A980EC3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_1289111FC84C8AB1FB4E5B4F0A98515F" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_UnsecuredLoansMember_1289111FC84C8AB1FB4E5B4F0A98515F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_1FCF6DC2D84ACE20B2F75B4F0A982B57" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_OneToFourFamilyResidentialMember_1FCF6DC2D84ACE20B2F75B4F0A982B57" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_6243C74C678D865590845B4F0A98F377" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_CommercialLandMember_6243C74C678D865590845B4F0A98F377" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_F8B68DC3B44690687CF55B4F0A98A673" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_IncomePropertyMultifamilyMember_F8B68DC3B44690687CF55B4F0A98A673" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_1E1683789E0AC6B74D8C5B4F0A986EF8" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_OwnerOccupiedMember_1E1683789E0AC6B74D8C5B4F0A986EF8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_4FED4B5D603F4DC8AC5D5B4F0A98EA16" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_LandAndAcquisitionMember_4FED4B5D603F4DC8AC5D5B4F0A98EA16" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_E5664ED29BF4F9D8B2B85B4F0A98EEDD" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_ResidentialConstructionMember_E5664ED29BF4F9D8B2B85B4F0A98EEDD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_BA591165E3003CC8927A5B4F0A986B96" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_BA591165E3003CC8927A5B4F0A986B96" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_C138989FBBA8358BF2D45B4F0A984A2A" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D6972C2E29A130E952DB5B4F0A98F645" xlink:to="loc_colb_OwnerOccupiedConstructionMember_C138989FBBA8358BF2D45B4F0A984A2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesRollForward" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_70698D018F4D9039DD495B4F0A9878D8" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_0BAA182425507CA6BC215B4F0A9893C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_0BAA182425507CA6BC215B4F0A9893C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_53B37398FD58CAE195385B4F0AA73F94" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_53B37398FD58CAE195385B4F0AA73F94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_FDFFD56779C28C8C8FBF5B4F0AA7F2EC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_FDFFD56779C28C8C8FBF5B4F0AA7F2EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanAndLeaseLosses" xlink:label="loc_us-gaap_ProvisionForLoanAndLeaseLosses_A0258E8ED8AEB6A296095B4F0AA7A09E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_us-gaap_ProvisionForLoanAndLeaseLosses_A0258E8ED8AEB6A296095B4F0AA7A09E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoanAndLeaseLossesSpecificReserve" xlink:label="loc_colb_LoanAndLeaseLossesSpecificReserve_88DED53E4D92291347AB5B4F0AA79B20" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_colb_LoanAndLeaseLossesSpecificReserve_88DED53E4D92291347AB5B4F0AA79B20" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoanAndLeaseLossesGeneralAllocation" xlink:label="loc_colb_LoanAndLeaseLossesGeneralAllocation_0B7C34C8F5AD5E73036E5B4F0AA76659" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRollForward_A8855A856D8DECAACEA45B4F0A989530" xlink:to="loc_colb_LoanAndLeaseLossesGeneralAllocation_0B7C34C8F5AD5E73036E5B4F0AA76659" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditAnalysisOfCreditQualityOfLoanPortfolioDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_577DE7AE71BB5360D2D15B4F09BD8ADE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_577DE7AE71BB5360D2D15B4F09BD8ADE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_1D3ED63D268AC562ED865B4F09BDE531" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_577DE7AE71BB5360D2D15B4F09BD8ADE" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_1D3ED63D268AC562ED865B4F09BDE531" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_1D3ED63D268AC562ED865B4F09BDE531" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_1D3ED63D268AC562ED865B4F09BDE531" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_2B6D5A78A015DACDF51A5B4F09BDEB65" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_2B6D5A78A015DACDF51A5B4F09BDEB65" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_BD073E369FEEB3AC54185B4F09BD9E3E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_SecuredLoansMember_BD073E369FEEB3AC54185B4F09BD9E3E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_0AA321575592923498AF5B4F09BD88E3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_UnsecuredLoansMember_0AA321575592923498AF5B4F09BD88E3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_00B0F9C33AEFADC23EB35B4F09BD54B5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_00B0F9C33AEFADC23EB35B4F09BD54B5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_295EF71E7D7E21C41E9B5B4F09BD9C4B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_OneToFourFamilyResidentialMember_295EF71E7D7E21C41E9B5B4F09BD9C4B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_60F7DCD047E42D210B4D5B4F09BD1B1C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_CommercialLandMember_60F7DCD047E42D210B4D5B4F09BD1B1C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_5B7E4DD8C1A73DD5E97F5B4F09BD75B6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_IncomePropertyMultifamilyMember_5B7E4DD8C1A73DD5E97F5B4F09BD75B6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_E76874BBD55A76A093B35B4F09BD263C" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_OwnerOccupiedMember_E76874BBD55A76A093B35B4F09BD263C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_4EB9E8B50C70304CE1E85B4F09BD9188" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_4EB9E8B50C70304CE1E85B4F09BD9188" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_A8CA6DDA2E2A164A7BD05B4F09BDABF2" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_LandAndAcquisitionMember_A8CA6DDA2E2A164A7BD05B4F09BDABF2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_FD6566B9B9DBBCE8074E5B4F09BDCFF7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_ResidentialConstructionMember_FD6566B9B9DBBCE8074E5B4F09BDCFF7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_C688EB6B006F71FFFEED5B4F09BD1126" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_C688EB6B006F71FFFEED5B4F09BD1126" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_AEB75B3B0E4A504462675B4F09BD06E4" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_colb_OwnerOccupiedConstructionMember_AEB75B3B0E4A504462675B4F09BD06E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_754CA7F777B3E7339DF65B4F09BD3454" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8F204915C6E4DFECB54D5B4F09BDF74C" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_754CA7F777B3E7339DF65B4F09BD3454" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentAxis" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_D86EE2FF64F9B8023E475B4F09BDB83E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_577DE7AE71BB5360D2D15B4F09BD8ADE" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_D86EE2FF64F9B8023E475B4F09BDB83E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentDomain" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_D86EE2FF64F9B8023E475B4F09BDB83E" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentDomain" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_D86EE2FF64F9B8023E475B4F09BDB83E" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PassMember" xlink:label="loc_us-gaap_PassMember_A2E3D0423704C13BF9BE5B4F09BD7BEB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:to="loc_us-gaap_PassMember_A2E3D0423704C13BF9BE5B4F09BD7BEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SpecialMentionMember" xlink:label="loc_us-gaap_SpecialMentionMember_2CCF471F4E233A4EF6285B4F09BD2149" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:to="loc_us-gaap_SpecialMentionMember_2CCF471F4E233A4EF6285B4F09BD2149" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubstandardMember" xlink:label="loc_us-gaap_SubstandardMember_0751612548E1A7F043F15B4F09BDC8F5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:to="loc_us-gaap_SubstandardMember_0751612548E1A7F043F15B4F09BDC8F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DoubtfulMember" xlink:label="loc_us-gaap_DoubtfulMember_CD8E0FA541AE2737C1325B4F09BD24CB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:to="loc_us-gaap_DoubtfulMember_CD8E0FA541AE2737C1325B4F09BD24CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UnlikelyToBeCollectedFinancingReceivableMember" xlink:label="loc_us-gaap_UnlikelyToBeCollectedFinancingReceivableMember_83953E13E9213982E4285B4F09BDE685" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_15FC7EA3B4004EB777905B4F09BD62B5" xlink:to="loc_us-gaap_UnlikelyToBeCollectedFinancingReceivableMember_83953E13E9213982E4285B4F09BDE685" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_22D7643C1670327A7C475B4F09BDD5ED" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_577DE7AE71BB5360D2D15B4F09BD8ADE" xlink:to="loc_colb_LoansByMajorCategoryAxis_22D7643C1670327A7C475B4F09BDD5ED" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_22D7643C1670327A7C475B4F09BDD5ED" xlink:to="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_22D7643C1670327A7C475B4F09BDD5ED" xlink:to="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_9666B723981250B071F15B4F09BDF3B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_9666B723981250B071F15B4F09BDF3B9" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_1BB58F3C038A71D0B4595B4F09BD949D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_8316ABE58884436C8A385B4F09BD131D" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_1BB58F3C038A71D0B4595B4F09BD949D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableGrossCarryingAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_A66AF8F8307B4E2C56AD5B4F09BD0AF6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:to="loc_us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_A66AF8F8307B4E2C56AD5B4F09BD0AF6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AcquisitionAccountingValuationDiscountOnCoveredLoans" xlink:label="loc_colb_AcquisitionAccountingValuationDiscountOnCoveredLoans_BF4A6B5A152869A156535B4F09BD6ABB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:to="loc_colb_AcquisitionAccountingValuationDiscountOnCoveredLoans_BF4A6B5A152869A156535B4F09BD6ABB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_25A4FAAF15E094D8EE2A5B4F09BD1500" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_25A4FAAF15E094D8EE2A5B4F09BD1500" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_8335E71B7B699AABF4495B4F09BD0195" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_641E4616D48A00BD66C95B4F09BD7C8A" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_8335E71B7B699AABF4495B4F09BD0195" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditChangesInAllowanceForUnfundedCommitmentsAndLettersOfCreditDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_7C60B306C6DF84FD32BD5B4F08667074" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FB6FBF385E95F54337C45B4F0856879E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_7C60B306C6DF84FD32BD5B4F08667074" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FB6FBF385E95F54337C45B4F0856879E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_50302B5AD0585D385A6C5B4F0866EDDA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_FB6FBF385E95F54337C45B4F0856879E" xlink:to="loc_srt_RangeAxis_50302B5AD0585D385A6C5B4F0866EDDA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_90DAEF3D9F267C3C19835B4F08662101_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_50302B5AD0585D385A6C5B4F0866EDDA" xlink:to="loc_srt_RangeMember_90DAEF3D9F267C3C19835B4F08662101_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_90DAEF3D9F267C3C19835B4F08662101" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_50302B5AD0585D385A6C5B4F0866EDDA" xlink:to="loc_srt_RangeMember_90DAEF3D9F267C3C19835B4F08662101" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_BCC5A3BF3B4E535564195B4F08665EF2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_90DAEF3D9F267C3C19835B4F08662101" xlink:to="loc_srt_MaximumMember_BCC5A3BF3B4E535564195B4F08665EF2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/AllowanceForLoanAndLeaseLossesAndUnfundedCommitmentsAndLettersOfCreditTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_87C3889A7EFE1EB18D235B4F0847C14A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_05C6BA0A4E4FD30312225B4F0847FFE7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_87C3889A7EFE1EB18D235B4F0847C14A" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_05C6BA0A4E4FD30312225B4F0847FFE7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_B1D3F26DE9906F130A6D5B4F084753CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_05C6BA0A4E4FD30312225B4F0847FFE7" xlink:to="loc_colb_LoansByMajorCategoryAxis_B1D3F26DE9906F130A6D5B4F084753CC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_B1D3F26DE9906F130A6D5B4F084753CC" xlink:to="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_B1D3F26DE9906F130A6D5B4F084753CC" xlink:to="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_39042D9C7620FCA753A35B4F08479065" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_39042D9C7620FCA753A35B4F08479065" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_862B3AD1357A960CE9815B4F0847CE85" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_C00908D516478674E9F45B4F084781A7" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_862B3AD1357A960CE9815B4F0847CE85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock" xlink:label="loc_us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_B8E26400186EE1F2F9425B4F08471D20" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_87C3889A7EFE1EB18D235B4F0847C14A" xlink:to="loc_us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_B8E26400186EE1F2F9425B4F08471D20" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ChangesInAllowanceForUnfundedLoanCommitmentsAndLettersOfCreditTextBlock" xlink:label="loc_colb_ChangesInAllowanceForUnfundedLoanCommitmentsAndLettersOfCreditTextBlock_3CA0D6461F0709611DCA5B4F0847D332" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_87C3889A7EFE1EB18D235B4F0847C14A" xlink:to="loc_colb_ChangesInAllowanceForUnfundedLoanCommitmentsAndLettersOfCreditTextBlock_3CA0D6461F0709611DCA5B4F0847D332" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock" xlink:label="loc_us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_55A8A2CE8924FD12FC915B4F08478199" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_87C3889A7EFE1EB18D235B4F0847C14A" xlink:to="loc_us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_55A8A2CE8924FD12FC915B4F08478199" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/BusinessCombinations" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_11897645386A990DF447074CA9DC5B51" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3790CCDC73BEFF04A50E074CA9CCD901" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_11897645386A990DF447074CA9DC5B51" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3790CCDC73BEFF04A50E074CA9CCD901" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_4BA940DB144DC9A3EDFE074CA9CCF2C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3790CCDC73BEFF04A50E074CA9CCD901" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_4BA940DB144DC9A3EDFE074CA9CCF2C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_03751BAFA451FD161EAF074CA9CC5848_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4BA940DB144DC9A3EDFE074CA9CCF2C2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_03751BAFA451FD161EAF074CA9CC5848_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_03751BAFA451FD161EAF074CA9CC5848" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4BA940DB144DC9A3EDFE074CA9CCF2C2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_03751BAFA451FD161EAF074CA9CC5848" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/BusinessCombinationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5474F1179022E59A6FD1EE81F4FDE7B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5474F1179022E59A6FD1EE81F4FDE7B8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_93719900F71488029A05EE81F4FDCDD3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5474F1179022E59A6FD1EE81F4FDE7B8" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_93719900F71488029A05EE81F4FDCDD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_93719900F71488029A05EE81F4FDCDD3" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_93719900F71488029A05EE81F4FDCDD3" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CompensationandemployeebenefitsMember" xlink:label="loc_colb_CompensationandemployeebenefitsMember_507275BA578D8DF6800DEE81F4FE5789" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_CompensationandemployeebenefitsMember_507275BA578D8DF6800DEE81F4FE5789" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OccupancyMember" xlink:label="loc_us-gaap_OccupancyMember_DB7F1583005B99BC921AEE81F4FE0F1D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_us-gaap_OccupancyMember_DB7F1583005B99BC921AEE81F4FE0F1D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AdvertisingandpromotionMember" xlink:label="loc_colb_AdvertisingandpromotionMember_9CB7C856C0866DC94A1AEE81F4FE1D15" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_AdvertisingandpromotionMember_9CB7C856C0866DC94A1AEE81F4FE1D15" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DataprocessingMember" xlink:label="loc_colb_DataprocessingMember_D3CDC9AA3EC909E3841CEE81F4FE6728" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_DataprocessingMember_D3CDC9AA3EC909E3841CEE81F4FE6728" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LegalandprofessionalfeesMember" xlink:label="loc_colb_LegalandprofessionalfeesMember_BB524DE3B4A222C05ECFEE81F4FEDAE4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_LegalandprofessionalfeesMember_BB524DE3B4A222C05ECFEE81F4FEDAE4" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TaxeslicensesandfeesMember" xlink:label="loc_colb_TaxeslicensesandfeesMember_B4FDC78A2E05819D5560EE81F4FFAAA7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_TaxeslicensesandfeesMember_B4FDC78A2E05819D5560EE81F4FFAAA7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OthernoninterestexpensesMember" xlink:label="loc_colb_OthernoninterestexpensesMember_0154562DF963C1F994B4EE81F4FFAB8E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F6D6D72F79AEECB5BED0EE81F4FD8541" xlink:to="loc_colb_OthernoninterestexpensesMember_0154562DF963C1F994B4EE81F4FFAB8E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_358BF8AF44F9831EF108EE81F4FF1EBE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5474F1179022E59A6FD1EE81F4FDE7B8" xlink:to="loc_us-gaap_StatementScenarioAxis_358BF8AF44F9831EF108EE81F4FF1EBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_8245ECA339712FA31ED7EE81F4FF800F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_358BF8AF44F9831EF108EE81F4FF1EBE" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_8245ECA339712FA31ED7EE81F4FF800F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_8245ECA339712FA31ED7EE81F4FF800F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_358BF8AF44F9831EF108EE81F4FF1EBE" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_8245ECA339712FA31ED7EE81F4FF800F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_8D5D9941F0B28AFCA9DEEE81F4FF289A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5474F1179022E59A6FD1EE81F4FDE7B8" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_8D5D9941F0B28AFCA9DEEE81F4FF289A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_8D5D9941F0B28AFCA9DEEE81F4FF289A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_8D5D9941F0B28AFCA9DEEE81F4FF289A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PacificContinentalMember" xlink:label="loc_colb_PacificContinentalMember_C9DC2B236D4DB4038AC7EE81F500A06D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345" xlink:to="loc_colb_PacificContinentalMember_C9DC2B236D4DB4038AC7EE81F500A06D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IntermountainCommunityBancorpMember" xlink:label="loc_colb_IntermountainCommunityBancorpMember_29A6074578BDDD1B70C6EE820E5CBC01" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_48B2FA1E8DC06E5EC564EE81F5005345" xlink:to="loc_colb_IntermountainCommunityBancorpMember_29A6074578BDDD1B70C6EE820E5CBC01" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_4DD14196F315FFD79DB8EE81F50597E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_4DD14196F315FFD79DB8EE81F50597E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_A3809D9DC31093649205EE81F506F835" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_A3809D9DC31093649205EE81F506F835" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:label="loc_us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1_8658769757D576EFA6E3EE81F5061D67" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1_8658769757D576EFA6E3EE81F5061D67" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_FB44E030E1302543AB4DEE81F50669B8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_FB44E030E1302543AB4DEE81F50669B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities_8FD0FED524630C6C6152EE81F5066221" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities_8FD0FED524630C6C6152EE81F5066221" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationFHLBStock" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationFHLBStock_6F77B3AEBF10753DEFB5EE81F507BB7F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationFHLBStock_6F77B3AEBF10753DEFB5EE81F507BB7F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_09DCAF7504DDFC718A1DEE81F507C64D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_09DCAF7504DDFC718A1DEE81F507C64D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationAccruedInterestReceivable" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationAccruedInterestReceivable_6BBC44FD4A8AA31F3EF0EE81F5074B42" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationAccruedInterestReceivable_6BBC44FD4A8AA31F3EF0EE81F5074B42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_8D84D472BAEB9657735FEE81F507193F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_8D84D472BAEB9657735FEE81F507193F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationOtherRealEstateOwned" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationOtherRealEstateOwned_B7A30EC1F9662871B03AEE81F5072738" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationOtherRealEstateOwned_B7A30EC1F9662871B03AEE81F5072738" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets_DE66FB3C033CB10D2E37EE81F507445E" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets_DE66FB3C033CB10D2E37EE81F507445E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationOtherAssets" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationOtherAssets_DEC6F85457069FBCE31AEE81F508E522" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationOtherAssets_DEC6F85457069FBCE31AEE81F508E522" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits_19FF8021349E389B40E8EE81F5082A89" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits_19FF8021349E389B40E8EE81F5082A89" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances_25D187B175936489EE78EE81F50864AC" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances_25D187B175936489EE78EE81F50864AC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationSubordinatedDebt" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationSubordinatedDebt_FE1111BC14E3F9EA49ABEE81F508335C" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationSubordinatedDebt_FE1111BC14E3F9EA49ABEE81F508335C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_JuniorSubordinatedNotes" xlink:label="loc_us-gaap_JuniorSubordinatedNotes_EDF21D40631C887698FCEE81F508D96A" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_JuniorSubordinatedNotes_EDF21D40631C887698FCEE81F508D96A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Businesscombinationpurchasepriceallocationsecuritiessoldunderagreementstorepurchase" xlink:label="loc_colb_Businesscombinationpurchasepriceallocationsecuritiessoldunderagreementstorepurchase_F9F23261C0A6296E0BFAEE81F5080087" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_Businesscombinationpurchasepriceallocationsecuritiessoldunderagreementstorepurchase_F9F23261C0A6296E0BFAEE81F5080087" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationOtherLiabilities" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationOtherLiabilities_A492436C299A7D5AA128EE81F5099FDC" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationOtherLiabilities_A492436C299A7D5AA128EE81F5099FDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_CCFED0034F58DC9568BFEE81F509CE35" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_CCFED0034F58DC9568BFEE81F509CE35" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount_5B8A36DEB9E097E1AF67EE81F509B293" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount_5B8A36DEB9E097E1AF67EE81F509B293" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_9BF6ABB746317B6D4CF2EE81F5098525" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_9BF6ABB746317B6D4CF2EE81F5098525" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_541B458CF6ECDAEC7C85EE81F50A234D" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_541B458CF6ECDAEC7C85EE81F50A234D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_7ED62F6F15F2FF1B2BDFEE81F50AC884" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_7ED62F6F15F2FF1B2BDFEE81F50AC884" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_20509BABD6F6E02BBD69EE81F50AEBA4" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F793C971F8F9D8BD75C6EE81F505D257" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_20509BABD6F6E02BBD69EE81F50AEBA4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/BusinessCombinationsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_EB49D2E9700C9652CD50A54E6E31A89D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_EB49D2E9700C9652CD50A54E6E31A89D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_D821D781AF01AE4A3D57A54E6E31F93C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_EB49D2E9700C9652CD50A54E6E31A89D" xlink:to="loc_us-gaap_StatementScenarioAxis_D821D781AF01AE4A3D57A54E6E31F93C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_2B8D1312DB67D1867B2AA54E6E319165_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_D821D781AF01AE4A3D57A54E6E31F93C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_2B8D1312DB67D1867B2AA54E6E319165_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_2B8D1312DB67D1867B2AA54E6E319165" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_D821D781AF01AE4A3D57A54E6E31F93C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_2B8D1312DB67D1867B2AA54E6E319165" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_45C0544E9DE0F1174409A54E6E3117DF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_EB49D2E9700C9652CD50A54E6E31A89D" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_45C0544E9DE0F1174409A54E6E3117DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9816A60112FF15D93E32A54E6E313DBD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_45C0544E9DE0F1174409A54E6E3117DF" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9816A60112FF15D93E32A54E6E313DBD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9816A60112FF15D93E32A54E6E313DBD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_45C0544E9DE0F1174409A54E6E3117DF" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9816A60112FF15D93E32A54E6E313DBD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PacificContinentalMember" xlink:label="loc_colb_PacificContinentalMember_34687576D99AEFB6725EA54E6E310A2E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9816A60112FF15D93E32A54E6E313DBD" xlink:to="loc_colb_PacificContinentalMember_34687576D99AEFB6725EA54E6E310A2E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures_3E400D011D3BC8E16234A54E6E3162BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures_3E400D011D3BC8E16234A54E6E3162BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_89C5A7AED316DD07A061A54E6E3142FA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_89C5A7AED316DD07A061A54E6E3142FA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount_91C606D2BE55542A22BEA54E6E3164B4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationGoodwillAmount_91C606D2BE55542A22BEA54E6E3164B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:label="loc_us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1_D3FE6460CC464D8A5651A54E6E316695" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1_D3FE6460CC464D8A5651A54E6E316695" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_5361A94CF2CDC53B21B1A54E6E414D13" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_5361A94CF2CDC53B21B1A54E6E414D13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_AAB50F6E233ABF9F8F30A54E6E41AB13" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_AAB50F6E233ABF9F8F30A54E6E41AB13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_5E49ED0B8E370FDAD38BA54E6E412A38" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_5E49ED0B8E370FDAD38BA54E6E412A38" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets_7098A1FB068F3F5D589FA54E6E41B962" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationAmortizableIntangibleAssets_7098A1FB068F3F5D589FA54E6E41B962" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Businesscombinationscoredepositintangiblepercentageofcoredeposits" xlink:label="loc_colb_Businesscombinationscoredepositintangiblepercentageofcoredeposits_F74EE4191AF31B11B731A54E6E41CE5F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_Businesscombinationscoredepositintangiblepercentageofcoredeposits_F74EE4191AF31B11B731A54E6E41CE5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_7F38250D0832F3CE2DF2A54E6E412FC2" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_7F38250D0832F3CE2DF2A54E6E412FC2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationOtherAssets" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationOtherAssets_7D19899977088A8D6172A54E6E41CD3A" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationOtherAssets_7D19899977088A8D6172A54E6E41CD3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_CAE6116A5C89886FBEC6A54E6E4186E4" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_CAE6116A5C89886FBEC6A54E6E4186E4" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits_1A78B773EA8E97B44F22A54E6E41C979" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationLiabilitiesDeposits_1A78B773EA8E97B44F22A54E6E41C979" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_4FA7A4910CA332CD6B5CA54E6E41FBD5" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_4FA7A4910CA332CD6B5CA54E6E41FBD5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances_270ED337E7546BFF3013A54E6E41038E" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_95214B28ABB9A20BE2E0A54E6E3197FA" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationFederalHomeLoanbankadvances_270ED337E7546BFF3013A54E6E41038E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/BusinessCombinationsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_05AE6324E0E3D09464135B4F0A88193A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9B1EB3332EAFA108D31A5B4F0A884349" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_05AE6324E0E3D09464135B4F0A88193A" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9B1EB3332EAFA108D31A5B4F0A884349" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_DA57EE5468A2E600F12B5B4F0A88E1E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9B1EB3332EAFA108D31A5B4F0A884349" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_DA57EE5468A2E600F12B5B4F0A88E1E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54C0C673DA277DF51AFF5B4F0A8886C7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_DA57EE5468A2E600F12B5B4F0A88E1E2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54C0C673DA277DF51AFF5B4F0A8886C7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54C0C673DA277DF51AFF5B4F0A8886C7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_DA57EE5468A2E600F12B5B4F0A88E1E2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54C0C673DA277DF51AFF5B4F0A8886C7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PacificContinentalMember" xlink:label="loc_colb_PacificContinentalMember_B004E098FC32EBCA2E575B4F0A883F94" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_54C0C673DA277DF51AFF5B4F0A8886C7" xlink:to="loc_colb_PacificContinentalMember_B004E098FC32EBCA2E575B4F0A883F94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_80A13F542A61948167415B4F0A88F33F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_05AE6324E0E3D09464135B4F0A88193A" xlink:to="loc_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_80A13F542A61948167415B4F0A88F33F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionProFormaInformationTextBlock" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaInformationTextBlock_F39C31F9E559F0B5D65D5B4F0A884ADF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_05AE6324E0E3D09464135B4F0A88193A" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaInformationTextBlock_F39C31F9E559F0B5D65D5B4F0A884ADF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock" xlink:label="loc_us-gaap_BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock_EB9909D1735AB8D09F795B4F0A880E39" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_05AE6324E0E3D09464135B4F0A88193A" xlink:to="loc_us-gaap_BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock_EB9909D1735AB8D09F795B4F0A880E39" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/CashAndCashEquivalents" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/CashAndCashEquivalentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_234FA8C7A26310DF9AD85B4F08669887" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable" xlink:label="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_6546CAE6FF53C4969F3E5B4F08665ECB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_234FA8C7A26310DF9AD85B4F08669887" xlink:to="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_6546CAE6FF53C4969F3E5B4F08665ECB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_24E6BB22572400B8010A5B4F0866CCF2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_6546CAE6FF53C4969F3E5B4F08665ECB" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_24E6BB22572400B8010A5B4F0866CCF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_144B9A566D77EF7017B55B4F08663B8B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_24E6BB22572400B8010A5B4F0866CCF2" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_144B9A566D77EF7017B55B4F08663B8B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_144B9A566D77EF7017B55B4F08663B8B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_24E6BB22572400B8010A5B4F0866CCF2" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_144B9A566D77EF7017B55B4F08663B8B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalReserveBankMember" xlink:label="loc_colb_FederalReserveBankMember_ADA98826A9FAD553ED565B4F08667229" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_144B9A566D77EF7017B55B4F08663B8B" xlink:to="loc_colb_FederalReserveBankMember_ADA98826A9FAD553ED565B4F08667229" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_07295F12B361D9D732215B4F0866B97F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_234FA8C7A26310DF9AD85B4F08669887" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_07295F12B361D9D732215B4F0866B97F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_EF2F9EE08D9F29A3331F06BF56F2D959" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_LossContingenciesTable_EF2F9EE08D9F29A3331F06BF56F2D959" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_StateofsaleleasebackactivityAxis" xlink:label="loc_colb_StateofsaleleasebackactivityAxis_0733573A04142FB35F5006BF56F226B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_EF2F9EE08D9F29A3331F06BF56F2D959" xlink:to="loc_colb_StateofsaleleasebackactivityAxis_0733573A04142FB35F5006BF56F226B5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_StateofsaleleasebackactivityDomain" xlink:label="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_StateofsaleleasebackactivityAxis_0733573A04142FB35F5006BF56F226B5" xlink:to="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_StateofsaleleasebackactivityDomain" xlink:label="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_StateofsaleleasebackactivityAxis_0733573A04142FB35F5006BF56F226B5" xlink:to="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_ID" xlink:label="loc_stpr_ID_92AAE505A95CAAC580DA06BF56F2183E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871" xlink:to="loc_stpr_ID_92AAE505A95CAAC580DA06BF56F2183E" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_WA" xlink:label="loc_stpr_WA_01C05A4F8D889712524E06BF56F2DBA7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_StateofsaleleasebackactivityDomain_4EC62663FED9196C9B1206BF56F24871" xlink:to="loc_stpr_WA_01C05A4F8D889712524E06BF56F2DBA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_FFC50DB5B7ECD9C3D0ED06BF56F2DFAE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_EF2F9EE08D9F29A3331F06BF56F2D959" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_FFC50DB5B7ECD9C3D0ED06BF56F2DFAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_E73CA28DE4CDBDC7FE1206BF56F2FC10_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_FFC50DB5B7ECD9C3D0ED06BF56F2DFAE" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_E73CA28DE4CDBDC7FE1206BF56F2FC10_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_E73CA28DE4CDBDC7FE1206BF56F2FC10" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_FFC50DB5B7ECD9C3D0ED06BF56F2DFAE" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_E73CA28DE4CDBDC7FE1206BF56F2FC10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_1A7681591D4BC28397AB06BF56F2F454" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_EF2F9EE08D9F29A3331F06BF56F2D959" xlink:to="loc_us-gaap_FinancialInstrumentAxis_1A7681591D4BC28397AB06BF56F2F454" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_1A7681591D4BC28397AB06BF56F2F454" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_1A7681591D4BC28397AB06BF56F2F454" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommitmentsToExtendCreditMember" xlink:label="loc_us-gaap_CommitmentsToExtendCreditMember_E2C55CD2F78C948CACCF06BF56F23F53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF" xlink:to="loc_us-gaap_CommitmentsToExtendCreditMember_E2C55CD2F78C948CACCF06BF56F23F53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StandbyLettersOfCreditMember" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_6A3382AE219E900BCE6606BF56F27EE6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_6A3382AE219E900BCE6606BF56F27EE6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLetterofCreditandotheroffbalancesheetliabilitiesMember" xlink:label="loc_colb_CommercialLetterofCreditandotheroffbalancesheetliabilitiesMember_32635CF31C72B0A0792706BF56F2585D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_044FC333732D61492BCB06BF56F219EF" xlink:to="loc_colb_CommercialLetterofCreditandotheroffbalancesheetliabilitiesMember_32635CF31C72B0A0792706BF56F2585D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_DB12622647AF8A3BFBF706BF56F2FA34" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_DB12622647AF8A3BFBF706BF56F2FA34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_63781ED1EED700AB999C06BF56F25661" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_63781ED1EED700AB999C06BF56F25661" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_E8F850CBEF1A8B04260F06BF56F2560F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_E8F850CBEF1A8B04260F06BF56F2560F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E2FCD7F1F0E2C722CE5206BF56F21B22" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E2FCD7F1F0E2C722CE5206BF56F21B22" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_7C58C46CD380304A0CB306BF56F28C7C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_7C58C46CD380304A0CB306BF56F28C7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_5CD5CE72AAF0E695D5DC06BF56F26204" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_5CD5CE72AAF0E695D5DC06BF56F26204" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_8514987C89B15E11B9CB06BF56F2A6D1" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_B8B2AB38C212BAB1135906BF56F2F1CE" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_8514987C89B15E11B9CB06BF56F2A6D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesRentExpenseSubleaseRentals1" xlink:label="loc_us-gaap_OperatingLeasesRentExpenseSubleaseRentals1_4CC628C354FEEADFDEDD06BF56F2BF74" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_OperatingLeasesRentExpenseSubleaseRentals1_4CC628C354FEEADFDEDD06BF56F2BF74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesRentExpenseNet" xlink:label="loc_us-gaap_OperatingLeasesRentExpenseNet_8E82C95798B77CDCDBEF06BF56F27296" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_OperatingLeasesRentExpenseNet_8E82C95798B77CDCDBEF06BF56F27296" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SaleLeasebackTransactionDate" xlink:label="loc_us-gaap_SaleLeasebackTransactionDate_1F76C083C4EF32C5D59E06BF56F2FDAE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_SaleLeasebackTransactionDate_1F76C083C4EF32C5D59E06BF56F2FDAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SaleLeasebackTransactionMonthlyRentalPayments" xlink:label="loc_us-gaap_SaleLeasebackTransactionMonthlyRentalPayments_B8FAF7B8EA7AF9407FDA06BF56F255BD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_SaleLeasebackTransactionMonthlyRentalPayments_B8FAF7B8EA7AF9407FDA06BF56F255BD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability" xlink:label="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_73B37C6133EE852E05C106BF56F23166" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_73B37C6133EE852E05C106BF56F23166" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SaleLeasebackTransactionDeferredGainGross" xlink:label="loc_us-gaap_SaleLeasebackTransactionDeferredGainGross_EE2BFB0F170F4D30676106BF56F2033C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_SaleLeasebackTransactionDeferredGainGross_EE2BFB0F170F4D30676106BF56F2033C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SaleLeasebackTransactionDeferredGainNet" xlink:label="loc_us-gaap_SaleLeasebackTransactionDeferredGainNet_E0F2B5BD0C3036B2173206BF56F24EE1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_9250B42CF4C0993BA75706BF56F2FD54" xlink:to="loc_us-gaap_SaleLeasebackTransactionDeferredGainNet_E0F2B5BD0C3036B2173206BF56F24EE1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/CommitmentsAndContingentLiabilitiesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_434B63F83DA785E274BC06BF59DFC8C5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_9036FACE411CE9EED48D06BF59DF07AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_434B63F83DA785E274BC06BF59DFC8C5" xlink:to="loc_us-gaap_StatementTable_9036FACE411CE9EED48D06BF59DF07AD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_ED9C9BEFFD1BD86E684006BF59DF0E57" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9036FACE411CE9EED48D06BF59DF07AD" xlink:to="loc_us-gaap_StatementScenarioAxis_ED9C9BEFFD1BD86E684006BF59DF0E57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_020103A9EE39CD8043F106BF59DFE55A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_ED9C9BEFFD1BD86E684006BF59DF0E57" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_020103A9EE39CD8043F106BF59DFE55A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_020103A9EE39CD8043F106BF59DFE55A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_ED9C9BEFFD1BD86E684006BF59DF0E57" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_020103A9EE39CD8043F106BF59DFE55A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_434B63F83DA785E274BC06BF59DFC8C5" xlink:to="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndDueFromBanks" xlink:label="loc_us-gaap_CashAndDueFromBanks_5AF83CE47ADA67EEB7E906BF59DF0F91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_CashAndDueFromBanks_5AF83CE47ADA67EEB7E906BF59DF0F91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="loc_us-gaap_InterestBearingDepositsInBanks_CEBD6335C25CFFBD876806BF59DF1BB5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_InterestBearingDepositsInBanks_CEBD6335C25CFFBD876806BF59DF1BB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_BA6CF92F8DC2B613428706BF59DFFF0C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_BA6CF92F8DC2B613428706BF59DFFF0C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_15721420693E99E0FBC906BF59DF33BF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_15721420693E99E0FBC906BF59DF33BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_033047CCD2DDB084D2FF06BF59DFF0C0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_033047CCD2DDB084D2FF06BF59DFF0C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankStock" xlink:label="loc_us-gaap_FederalHomeLoanBankStock_56C132521526F1034C6506BF59DF1AD4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_FederalHomeLoanBankStock_56C132521526F1034C6506BF59DF1AD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_D01E213AC69EB7E86E5A06BF59DF78F6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_D01E213AC69EB7E86E5A06BF59DF78F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_D14A1F9FCC91D6640ADA06BF59DF8D4B" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_D14A1F9FCC91D6640ADA06BF59DF8D4B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_2F18B152A111FB4ED12D06BF59DFF53F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_2F18B152A111FB4ED12D06BF59DFF53F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_F7C46784144957169B1C06BF59DF9A43" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_F7C46784144957169B1C06BF59DF9A43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestReceivable" xlink:label="loc_us-gaap_InterestReceivable_257586265996791EFCAD06BF59DF263B" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_InterestReceivable_257586265996791EFCAD06BF59DF263B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_82045E2B56F3833D9C5606BF59DF710B" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_82045E2B56F3833D9C5606BF59DF710B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateAcquiredThroughForeclosure" xlink:label="loc_us-gaap_RealEstateAcquiredThroughForeclosure_6D5F1B6E01022BC901D806BF59DF4837" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_RealEstateAcquiredThroughForeclosure_6D5F1B6E01022BC901D806BF59DF4837" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_149D3E7AB2DC1AB0C61B06BF59DFF733" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_Goodwill_149D3E7AB2DC1AB0C61B06BF59DFF733" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_B799248084F5872B596906BF59DF8C4B" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_B799248084F5872B596906BF59DF8C4B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_C1F8CAAA42FBBAAC569A06BF59DF83BF" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_OtherAssets_C1F8CAAA42FBBAAC569A06BF59DF83BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_BD52E71C82B5400FE9CE06BF59DFFB4A" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F7F1639512B53E8992F706BF59DFC554" xlink:to="loc_us-gaap_Assets_BD52E71C82B5400FE9CE06BF59DFFB4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_434B63F83DA785E274BC06BF59DFC8C5" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestBearingDepositLiabilities" xlink:label="loc_us-gaap_NoninterestBearingDepositLiabilities_C7DA9884ADE3258AA71A06BF59DFB554" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_NoninterestBearingDepositLiabilities_C7DA9884ADE3258AA71A06BF59DFB554" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="loc_us-gaap_InterestBearingDepositLiabilities_EF5DE1257AEA9BD1063D06BF59DFDCB4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_InterestBearingDepositLiabilities_EF5DE1257AEA9BD1063D06BF59DFDCB4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Deposits" xlink:label="loc_us-gaap_Deposits_E6E0459A248D4765629006BF59DFEC56" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_Deposits_E6E0459A248D4765629006BF59DFEC56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesLongTerm" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_EF88B00BD97A551EED5A06BF59DF8702" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_EF88B00BD97A551EED5A06BF59DF8702" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchase" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_9E1EA7B292DD51D1A8AA06BF59DF9026" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_9E1EA7B292DD51D1A8AA06BF59DF9026" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedDebt" xlink:label="loc_us-gaap_SubordinatedDebt_E52073FB9D6E67AE588606BF59DF2D21" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_SubordinatedDebt_E52073FB9D6E67AE588606BF59DF2D21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_JuniorSubordinatedNotes" xlink:label="loc_us-gaap_JuniorSubordinatedNotes_8252F11DAD8F9A17E90B06BF59DF0D57" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_JuniorSubordinatedNotes_8252F11DAD8F9A17E90B06BF59DF0D57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="loc_us-gaap_OtherLiabilities_BF61010BE18A8A32FA9206BF59DFF252" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_OtherLiabilities_BF61010BE18A8A32FA9206BF59DFF252" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_822645201587BAA9EFBA06BF59DF1BA4" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_Liabilities_822645201587BAA9EFBA06BF59DF1BA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_70889799B2032D26A2F206BF59DFC4F2" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_388C2829AE51B748C97506BF59DFEE42" xlink:to="loc_us-gaap_CommitmentsAndContingencies_70889799B2032D26A2F206BF59DFC4F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_434B63F83DA785E274BC06BF59DFC8C5" xlink:to="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_EB87B2E0626A5008044506BF59DFF2B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_EB87B2E0626A5008044506BF59DFF2B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_5BD5BE2E5CC30C551D3A06BF59DF6D7D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_5BD5BE2E5CC30C551D3A06BF59DF6D7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_6FDB7206707CF9A420BD06BF59DF1D73" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_CommonStockSharesIssued_6FDB7206707CF9A420BD06BF59DF1D73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_382A3605A2FF7E634E5206BF59DF9B76" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_CommonStockValue_382A3605A2FF7E634E5206BF59DF9B76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_3B501A68505687571E7206BF59DF9709" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_3B501A68505687571E7206BF59DF9709" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_D3AE888D68F2322B50A506BF59DFC587" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_D3AE888D68F2322B50A506BF59DFC587" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_05A1F6928D85E32E6D9906BF59DF7608" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_StockholdersEquity_05A1F6928D85E32E6D9906BF59DF7608" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_9E4776122B0E686E272E06BF59DF5086" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_5EA6F775C1E74ED4D02806BF59DFBA2F" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_9E4776122B0E686E272E06BF59DF5086" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_42DC1CE0A2ED333F870306BF59CFCE19" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_84707780DE5EFF6AB78A06BF59CFE02F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_42DC1CE0A2ED333F870306BF59CFCE19" xlink:to="loc_us-gaap_StatementTable_84707780DE5EFF6AB78A06BF59CFE02F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_6D43A904A67A00A6FFD106BF59CF882B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_84707780DE5EFF6AB78A06BF59CFE02F" xlink:to="loc_us-gaap_StatementScenarioAxis_6D43A904A67A00A6FFD106BF59CF882B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_94682A574BC9770BE4C606BF59CFCFD7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_6D43A904A67A00A6FFD106BF59CF882B" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_94682A574BC9770BE4C606BF59CFCFD7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_94682A574BC9770BE4C606BF59CFCFD7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_6D43A904A67A00A6FFD106BF59CF882B" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_94682A574BC9770BE4C606BF59CFCFD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockNoParValue" xlink:label="loc_us-gaap_CommonStockNoParValue_58D96AFD47800C90CC6C06BF59CFF62E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42DC1CE0A2ED333F870306BF59CFCE19" xlink:to="loc_us-gaap_CommonStockNoParValue_58D96AFD47800C90CC6C06BF59CFF62E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_C33DE5453170399864B00736CBD6E069" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42DC1CE0A2ED333F870306BF59CFCE19" xlink:to="loc_us-gaap_CommonStockSharesIssued_C33DE5453170399864B00736CBD6E069" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_4030BC5702C456D9763A0803C0092841" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_StatementTable_4030BC5702C456D9763A0803C0092841" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4F57138E82A34857386B0803C0092BD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4030BC5702C456D9763A0803C0092841" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4F57138E82A34857386B0803C0092BD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_2C9B9AEE15036CDBCEDA0803C009E01F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4F57138E82A34857386B0803C0092BD2" xlink:to="loc_us-gaap_EquityComponentDomain_2C9B9AEE15036CDBCEDA0803C009E01F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_2C9B9AEE15036CDBCEDA0803C009E01F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4F57138E82A34857386B0803C0092BD2" xlink:to="loc_us-gaap_EquityComponentDomain_2C9B9AEE15036CDBCEDA0803C009E01F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_5A7DDA7DFC15168255BB0803C0099CCB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2C9B9AEE15036CDBCEDA0803C009E01F" xlink:to="loc_us-gaap_CommonStockMember_5A7DDA7DFC15168255BB0803C0099CCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_4787A2E283E73809BE100803C009F227" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4030BC5702C456D9763A0803C0092841" xlink:to="loc_us-gaap_StatementScenarioAxis_4787A2E283E73809BE100803C009F227" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_1D91CC9E478A11D2C6E20803C0096510_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_4787A2E283E73809BE100803C009F227" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_1D91CC9E478A11D2C6E20803C0096510_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_1D91CC9E478A11D2C6E20803C0096510" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_4787A2E283E73809BE100803C009F227" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_1D91CC9E478A11D2C6E20803C0096510" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_44437F7294717436F0ED0803C009844B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_44437F7294717436F0ED0803C009844B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_B524D59E8380FCD6CA120803C009A169" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_44437F7294717436F0ED0803C009844B" xlink:to="loc_us-gaap_NetIncomeLoss_B524D59E8380FCD6CA120803C009A169" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_44437F7294717436F0ED0803C009844B" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanAndLeaseLosses" xlink:label="loc_us-gaap_ProvisionForLoanAndLeaseLosses_786AD2AE6263154907A80803C0098255" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_ProvisionForLoanAndLeaseLosses_786AD2AE6263154907A80803C0098255" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_BAF2BCFF019B2EEE95120803C0098B30" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_ShareBasedCompensation_BAF2BCFF019B2EEE95120803C0098B30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepreciationAmortizationAndAccretionNet" xlink:label="loc_us-gaap_DepreciationAmortizationAndAccretionNet_CF2CBE32CC916A51FE3D0803C009541F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_DepreciationAmortizationAndAccretionNet_CF2CBE32CC916A51FE3D0803C009541F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_12AF266894683A03D5BE0803C009DBED" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_12AF266894683A03D5BE0803C009DBED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfOtherAssets" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets_5C96959421F3558A88E20803C009119B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_GainLossOnSaleOfOtherAssets_5C96959421F3558A88E20803C009119B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NetgainonsaleandvaluationadjustmentsofOREO" xlink:label="loc_colb_NetgainonsaleandvaluationadjustmentsofOREO_CD038A5490E483CEBF690803C0090956" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_colb_NetgainonsaleandvaluationadjustmentsofOREO_CD038A5490E483CEBF690803C0090956" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Gainonsaleofmerchantcardservicesportfolio" xlink:label="loc_colb_Gainonsaleofmerchantcardservicesportfolio_333058B9D0712B21B5C30803C01924FB" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_colb_Gainonsaleofmerchantcardservicesportfolio_333058B9D0712B21B5C30803C01924FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfInsuranceBlock" xlink:label="loc_us-gaap_GainLossOnSaleOfInsuranceBlock_3E005FCC56A42DEF3F150803C019B72E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_GainLossOnSaleOfInsuranceBlock_3E005FCC56A42DEF3F150803C019B72E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FDIClosssharingagreementearlyterminationpretaxcharge" xlink:label="loc_colb_FDIClosssharingagreementearlyterminationpretaxcharge_0BE78208783D6134E0DF0803C0199E29" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_colb_FDIClosssharingagreementearlyterminationpretaxcharge_0BE78208783D6134E0DF0803C0199E29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale" xlink:label="loc_us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale_860EA278AD893604D2790803C019A5BB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale_860EA278AD893604D2790803C019A5BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfLoansHeldForSale" xlink:label="loc_us-gaap_ProceedsFromSaleOfLoansHeldForSale_3C99ACD60227385770480803C019E5EB" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_ProceedsFromSaleOfLoansHeldForSale_3C99ACD60227385770480803C019E5EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_E32F004ABDB7696A57710803C0195617" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_E32F004ABDB7696A57710803C0195617" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_E6D0F01DEFED53AF65470803C009CF6B" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInInterestAndDividendsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInInterestAndDividendsReceivable_D14C15E88DAF247F99950803C019901F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:to="loc_us-gaap_IncreaseDecreaseInInterestAndDividendsReceivable_D14C15E88DAF247F99950803C019901F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:label="loc_us-gaap_IncreaseDecreaseInInterestPayableNet_05D80D9D038536F0CE810803C019E59F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:to="loc_us-gaap_IncreaseDecreaseInInterestPayableNet_05D80D9D038536F0CE810803C019E59F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_8B90505BE066167001FC0803C0194432" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_8B90505BE066167001FC0803C0194432" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_14A7267D4DAD0DD8A18C0803C0192549" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3B70CA143AF754C509240803C0196F72" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_14A7267D4DAD0DD8A18C0803C0192549" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_BE216448248480408AE60803C01917F1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_44437F7294717436F0ED0803C009844B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_BE216448248480408AE60803C01917F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:label="loc_us-gaap_PaymentsForProceedsFromLoansAndLeases_2F80EBD7CC000E2E5A710803C0192D11" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_PaymentsForProceedsFromLoansAndLeases_2F80EBD7CC000E2E5A710803C0192D11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_5BDB25F05B3A794A5B500803C019EB60" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_5BDB25F05B3A794A5B500803C019EB60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireLoansHeldForInvestment" xlink:label="loc_us-gaap_PaymentsToAcquireLoansHeldForInvestment_4FE9C821E21F99D07EA30803C01909E2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_PaymentsToAcquireLoansHeldForInvestment_4FE9C821E21F99D07EA30803C01909E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_54328D19CAF84E9D3E5A0803C0192081" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_54328D19CAF84E9D3E5A0803C0192081" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireFederalHomeLoanBankStock" xlink:label="loc_us-gaap_PaymentsToAcquireFederalHomeLoanBankStock_B3D064012636DED86B320803C0199062" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_PaymentsToAcquireFederalHomeLoanBankStock_B3D064012636DED86B320803C0199062" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ProceedsfromFDICforreimbursementonlosssharingasset" xlink:label="loc_colb_ProceedsfromFDICforreimbursementonlosssharingasset_2D334C7F5DA1E35BD2300803C0191E9C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_colb_ProceedsfromFDICforreimbursementonlosssharingasset_2D334C7F5DA1E35BD2300803C0191E9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_15EB47DC87113A02FA6B0803C019714A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_15EB47DC87113A02FA6B0803C019714A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesEquity" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesEquity_F31109C1E657B11093860803C019E9C3" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesEquity_F31109C1E657B11093860803C019E9C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_5FDE02E7471044E7180D0803C0192C40" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_5FDE02E7471044E7180D0803C0192C40" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ProceedsFromSalesOfLoansHeldForInvestmentAndOtherAssets" xlink:label="loc_colb_ProceedsFromSalesOfLoansHeldForInvestmentAndOtherAssets_9B756FD82CB64311C55E0803C0198914" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_colb_ProceedsFromSalesOfLoansHeldForInvestmentAndOtherAssets_9B756FD82CB64311C55E0803C0198914" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Proceedsfromsaleofmerchantcardservicesportfolio" xlink:label="loc_colb_Proceedsfromsaleofmerchantcardservicesportfolio_D4A11F89978C5422D45B0803C0194B2C" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_colb_Proceedsfromsaleofmerchantcardservicesportfolio_D4A11F89978C5422D45B0803C0194B2C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfFederalHomeLoanBankStock" xlink:label="loc_us-gaap_ProceedsFromSaleOfFederalHomeLoanBankStock_0B6A309AC9C67702FC3C0803C019D468" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromSaleOfFederalHomeLoanBankStock_0B6A309AC9C67702FC3C0803C019D468" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfForeclosedAssets" xlink:label="loc_us-gaap_ProceedsFromSaleOfForeclosedAssets_03CC6C1FD797349F34FE0803C0191471" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromSaleOfForeclosedAssets_03CC6C1FD797349F34FE0803C0191471" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromLifeInsurancePolicies" xlink:label="loc_us-gaap_ProceedsFromLifeInsurancePolicies_C93550C4873C9BE1A6440803C019B245" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_ProceedsFromLifeInsurancePolicies_C93550C4873C9BE1A6440803C019B245" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PaymentfromtoFDICtoterminatelosssharingagreements" xlink:label="loc_colb_PaymentfromtoFDICtoterminatelosssharingagreements_678209D5458D1A8E6B140803C019CEE5" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_colb_PaymentfromtoFDICtoterminatelosssharingagreements_678209D5458D1A8E6B140803C019CEE5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PaymenttoFDICRelatedtoLossSharingAsset" xlink:label="loc_colb_PaymenttoFDICRelatedtoLossSharingAsset_88C39F8F9EC038ED8E9A0803C019E597" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_colb_PaymenttoFDICRelatedtoLossSharingAsset_88C39F8F9EC038ED8E9A0803C019E597" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAcquiredFromAcquisition" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_1686173D8B0CE6EA6F200803C01957E9" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_CashAcquiredFromAcquisition_1686173D8B0CE6EA6F200803C01957E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_6ABBDFBA38D8887D31F70803C0190519" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_27234DBEDC65DA80A2EC0803C0192E04" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_6ABBDFBA38D8887D31F70803C0190519" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInDeposits" xlink:label="loc_us-gaap_IncreaseDecreaseInDeposits_739EA017522CC4BA3DBD0803C019FB21" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_IncreaseDecreaseInDeposits_739EA017522CC4BA3DBD0803C019FB21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet" xlink:label="loc_us-gaap_IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet_BFE925EEDC307C62C1020803C019029F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet_BFE925EEDC307C62C1020803C019029F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_5A243C8009512BA367CD0803C0191DEF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_5A243C8009512BA367CD0803C0191DEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromFederalHomeLoanBankAdvances" xlink:label="loc_us-gaap_ProceedsFromFederalHomeLoanBankAdvances_6431BEAF95797B6E72160803C0191263" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_ProceedsFromFederalHomeLoanBankAdvances_6431BEAF95797B6E72160803C0191263" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromFederalHomeLoanBankBorrowings" xlink:label="loc_us-gaap_ProceedsFromFederalHomeLoanBankBorrowings_841A55856D3C39EDEDD20803C01942AA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_ProceedsFromFederalHomeLoanBankBorrowings_841A55856D3C39EDEDD20803C01942AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForFederalHomeLoanBankAdvances" xlink:label="loc_us-gaap_PaymentsForFederalHomeLoanBankAdvances_D249E113592BEBBB1C5A0803C019F0EB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_PaymentsForFederalHomeLoanBankAdvances_D249E113592BEBBB1C5A0803C019F0EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings" xlink:label="loc_us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings_5AA75901F59C5518FF680803C0197739" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings_5AA75901F59C5518FF680803C0197739" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xlink:label="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_73922E6FD54191BB6AA60803C0193214" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_73922E6FD54191BB6AA60803C0193214" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_3D101B366923113613FE0803C0192199" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_3D101B366923113613FE0803C0192199" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfSubordinatedDebt" xlink:label="loc_us-gaap_RepaymentsOfSubordinatedDebt_739C766061E88C1A96D70803C019E0FF" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_RepaymentsOfSubordinatedDebt_739C766061E88C1A96D70803C019E0FF" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Repaymentoftermrepurchaseagreement" xlink:label="loc_colb_Repaymentoftermrepurchaseagreement_A9586A52AFD1F43EE9120803C0196AEF" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_colb_Repaymentoftermrepurchaseagreement_A9586A52AFD1F43EE9120803C0196AEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfEquity_8BAFE42490A47FE66AD70803C019B05E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfEquity_8BAFE42490A47FE66AD70803C019B05E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_3649E25F2C651D3F655D0803C019FA5C" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_3649E25F2C651D3F655D0803C019FA5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_02F645723A716F32C6E40803C019A569" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_02F645723A716F32C6E40803C019A569" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_E6BF41784B6B9C0F52410803C019E536" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_8D800F00866C20FF825C0803C019E048" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_E6BF41784B6B9C0F52410803C019E536" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_D86FCB682D92F1BD201A0803C019B748" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_D86FCB682D92F1BD201A0803C019B748" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_D1FB5563ACF024D38F940803C019FDEA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_D1FB5563ACF024D38F940803C019FDEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_DCDACB66B3990B76F2580803C0196649" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_DCDACB66B3990B76F2580803C0196649" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestPaidNet" xlink:label="loc_us-gaap_InterestPaidNet_F6D50079B2D5F63A01430803C0199E0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_DCDACB66B3990B76F2580803C0196649" xlink:to="loc_us-gaap_InterestPaidNet_F6D50079B2D5F63A01430803C0199E0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="loc_us-gaap_IncomeTaxesPaid_1F98043C3E5A1EEE73260803C019AC1E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_DCDACB66B3990B76F2580803C0196649" xlink:to="loc_us-gaap_IncomeTaxesPaid_1F98043C3E5A1EEE73260803C019AC1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:label="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_194CB7417634FDB938B70803C019987A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_194CB7417634FDB938B70803C019987A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransferToOtherRealEstate" xlink:label="loc_us-gaap_TransferToOtherRealEstate_A5B0C6088DB5D13087B50803C0197BC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_194CB7417634FDB938B70803C019987A" xlink:to="loc_us-gaap_TransferToOtherRealEstate_A5B0C6088DB5D13087B50803C0197BC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssued1" xlink:label="loc_us-gaap_StockIssued1_BBDC8F8FD975FD8394E20803C0191741" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoncashInvestingAndFinancingItemsAbstract_194CB7417634FDB938B70803C019987A" xlink:to="loc_us-gaap_StockIssued1_BBDC8F8FD975FD8394E20803C0191741" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_20060619FAD4E6D48E670803C0197E16" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_20060619FAD4E6D48E670803C0197E16" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Changeindividendspayableonunvestedshares" xlink:label="loc_colb_Changeindividendspayableonunvestedshares_91AA43E0989FB3F87E100803C01913A9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_594041F1DFCA605F7F0C0803C009276C" xlink:to="loc_colb_Changeindividendspayableonunvestedshares_91AA43E0989FB3F87E100803C01913A9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_7DBA185106D8C5572DB6A59154293D3E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StatementTable_7DBA185106D8C5572DB6A59154293D3E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_06A195D86E1C6A4169BBA59154294FDE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_7DBA185106D8C5572DB6A59154293D3E" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_06A195D86E1C6A4169BBA59154294FDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_06A195D86E1C6A4169BBA59154294FDE" xlink:to="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_06A195D86E1C6A4169BBA59154294FDE" xlink:to="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201609Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201609Member_0E1D72809E534FC8F586A5915429CBB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973" xlink:to="loc_us-gaap_AccountingStandardsUpdate201609Member_0E1D72809E534FC8F586A5915429CBB9" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingStandardsUpdate201802Member" xlink:label="loc_colb_AccountingStandardsUpdate201802Member_174D73BF9AA6EC7099AFA591542978FB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973" xlink:to="loc_colb_AccountingStandardsUpdate201802Member_174D73BF9AA6EC7099AFA591542978FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201601Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201601Member_282A17639390ADDED12BA591544973C5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E156F075C537ED2378A9A59154292973" xlink:to="loc_us-gaap_AccountingStandardsUpdate201601Member_282A17639390ADDED12BA591544973C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_263FF6583B86241A2C8AA5915429346E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_7DBA185106D8C5572DB6A59154293D3E" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_263FF6583B86241A2C8AA5915429346E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_263FF6583B86241A2C8AA5915429346E" xlink:to="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_263FF6583B86241A2C8AA5915429346E" xlink:to="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_479D19FFEA66E3DC23AEA59154292DCE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:to="loc_us-gaap_PreferredStockMember_479D19FFEA66E3DC23AEA59154292DCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_E7D48801BF96769EBCFBA591542966B9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:to="loc_us-gaap_CommonStockMember_E7D48801BF96769EBCFBA591542966B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_322C6BC7F89BA03611D9A5915429DC7E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:to="loc_us-gaap_RetainedEarningsMember_322C6BC7F89BA03611D9A5915429DC7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_E357B6C88E14C7CE2DDDA59154298FED" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_C565F9E1B2A2D3F88AB6A59154296F82" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_E357B6C88E14C7CE2DDDA59154298FED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_112DE84C1E5990095A2FA5915429335E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_112DE84C1E5990095A2FA5915429335E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_B0ABE551167B29F7FE9DA591542987D4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockholdersEquity_B0ABE551167B29F7FE9DA591542987D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaap_SharesIssued_97F05DCEB543BB1DF370A59154295C70" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_SharesIssued_97F05DCEB543BB1DF370A59154295C70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A349847E18FE3AF6C87CA5915429CF11" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_NetIncomeLoss_A349847E18FE3AF6C87CA5915429CF11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_79D4C934708CBC70DB12A591542929D1" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_79D4C934708CBC70DB12A591542929D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_5161CB2C5ACDFF6EC33BA59154299FCD" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_5161CB2C5ACDFF6EC33BA59154299FCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_4C28D79841FB3A4CFC43A59154290A4A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_4C28D79841FB3A4CFC43A59154290A4A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_StockAdjustmentValueDeferredCompensation" xlink:label="loc_colb_StockAdjustmentValueDeferredCompensation_12A683A36EC51CB29DDFA59154295EB7" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_colb_StockAdjustmentValueDeferredCompensation_12A683A36EC51CB29DDFA59154295EB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_2F810E85644D81DCCC3DA5915429613A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_2F810E85644D81DCCC3DA5915429613A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_0A4962D0F0FC100F83B7A591543969EC" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_0A4962D0F0FC100F83B7A591543969EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_014DBF500413762FAB94A59154396781" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_014DBF500413762FAB94A59154396781" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_72B5A8C5266A2F0C6EDBA5915439335E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_72B5A8C5266A2F0C6EDBA5915439335E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConversionOfStockSharesConverted1" xlink:label="loc_us-gaap_ConversionOfStockSharesConverted1_09B2E74E8A6FE6D3CD40A59154397199" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_ConversionOfStockSharesConverted1_09B2E74E8A6FE6D3CD40A59154397199" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConversionOfStockAmountConverted1" xlink:label="loc_us-gaap_ConversionOfStockAmountConverted1_B5E9030E19EE6D134A0EA5915439088A" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_ConversionOfStockAmountConverted1_B5E9030E19EE6D134A0EA5915439088A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConversionOfStockSharesIssued1" xlink:label="loc_us-gaap_ConversionOfStockSharesIssued1_7D55338A706F73FA07C2A5915439B849" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_ConversionOfStockSharesIssued1_7D55338A706F73FA07C2A5915439B849" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConversionOfStockAmountIssued1" xlink:label="loc_us-gaap_ConversionOfStockAmountIssued1_4D9B9E99C8C9F7B6F4DDA5915439D151" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_ConversionOfStockAmountIssued1_4D9B9E99C8C9F7B6F4DDA5915439D151" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_F2BA21602DBE568BDDFFA59154395840" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_F2BA21602DBE568BDDFFA59154395840" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_9A99BA3D01131F9BD114A591543952BC" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_9A99BA3D01131F9BD114A591543952BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_41166E8FDC583F2C4466A59154396DC2" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_41166E8FDC583F2C4466A59154396DC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRedeemedOrCalledDuringPeriodValue" xlink:label="loc_us-gaap_StockRedeemedOrCalledDuringPeriodValue_2623401FBE88076A7A86A59154393F63" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_StockRedeemedOrCalledDuringPeriodValue_2623401FBE88076A7A86A59154393F63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DividendsPreferredStockCash" xlink:label="loc_us-gaap_DividendsPreferredStockCash_951B00A7A0B0739D1784A5915439A859" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_DividendsPreferredStockCash_951B00A7A0B0739D1784A5915439A859" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DividendsCommonStockCash" xlink:label="loc_us-gaap_DividendsCommonStockCash_185E583221C3AECDF995A59154392C90" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_DividendsCommonStockCash_185E583221C3AECDF995A59154392C90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockDividendsPerShareCashPaid" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_384C940F357FFE6DDD5CA59154391B70" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_PreferredStockDividendsPerShareCashPaid_384C940F357FFE6DDD5CA59154391B70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockDividendsPerShareCashPaid" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_228DDE53F7EC734061E5A59154397E8B" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A48B906A96160437F759A5915429E457" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_228DDE53F7EC734061E5A59154397E8B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_B4EA0717EE81626F7F57A54E6E9E1C97" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_BC31037C29FC6A0310F2A54E6E9E7D44" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_B4EA0717EE81626F7F57A54E6E9E1C97" xlink:to="loc_us-gaap_StatementTable_BC31037C29FC6A0310F2A54E6E9E7D44" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_D582056CECE84E6A835AA54E6E9E1359" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_BC31037C29FC6A0310F2A54E6E9E7D44" xlink:to="loc_dei_LegalEntityAxis_D582056CECE84E6A835AA54E6E9E1359" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_C94DC4CFD8D136FFB8E1A54E6E9E9A12_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_D582056CECE84E6A835AA54E6E9E1359" xlink:to="loc_dei_EntityDomain_C94DC4CFD8D136FFB8E1A54E6E9E9A12_default" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_C94DC4CFD8D136FFB8E1A54E6E9E9A12" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_D582056CECE84E6A835AA54E6E9E1359" xlink:to="loc_dei_EntityDomain_C94DC4CFD8D136FFB8E1A54E6E9E9A12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A446927D08D97A0D38ADA54E6E9E7F3D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B4EA0717EE81626F7F57A54E6E9E1C97" xlink:to="loc_us-gaap_NetIncomeLoss_A446927D08D97A0D38ADA54E6E9E7F3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_3FA273BB6C5B25ABBC74A54E6E9E7AA7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B4EA0717EE81626F7F57A54E6E9E1C97" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_3FA273BB6C5B25ABBC74A54E6E9E7AA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesUnrealizedGainLossAbstract" xlink:label="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_684B4CED621BE5B1E6DDA54E6E9E9607" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_3FA273BB6C5B25ABBC74A54E6E9E7AA7" xlink:to="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_684B4CED621BE5B1E6DDA54E6E9E9607" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_BF59C85C6665F2B5320FA54E6E9E59CD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_684B4CED621BE5B1E6DDA54E6E9E9607" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_BF59C85C6665F2B5320FA54E6E9E59CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_B6AD4779E3CB792FF3A3A54E6E9ECF7E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_684B4CED621BE5B1E6DDA54E6E9E9607" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_B6AD4779E3CB792FF3A3A54E6E9ECF7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_5006B6C23474B3EF3E41A54E6E9E97BC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_684B4CED621BE5B1E6DDA54E6E9E9607" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_5006B6C23474B3EF3E41A54E6E9E97BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract_F12C8A54204881E0905BA54E6E9EED89" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_3FA273BB6C5B25ABBC74A54E6E9E7AA7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract_F12C8A54204881E0905BA54E6E9EED89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax_445F5C98B99045DCCD27A54E6E9E90AB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract_F12C8A54204881E0905BA54E6E9EED89" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax_445F5C98B99045DCCD27A54E6E9E90AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_51EF14521AD65A947676A54E6E9ED745" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract_F12C8A54204881E0905BA54E6E9EED89" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_51EF14521AD65A947676A54E6E9ED745" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_DD296135D32DC5ACD2C3A54E6E9E8F40" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParentAbstract_F12C8A54204881E0905BA54E6E9EED89" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_DD296135D32DC5ACD2C3A54E6E9E8F40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_2A5CE8DFB0A62E3A2C3CA54E6EAE3832" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_3FA273BB6C5B25ABBC74A54E6E9E7AA7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_2A5CE8DFB0A62E3A2C3CA54E6EAE3832" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_24A1CC638DABD6678C63A54E6EAE3722" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B4EA0717EE81626F7F57A54E6E9E1C97" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_24A1CC638DABD6678C63A54E6EAE3722" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_73E105CA1C59A2BF46E65B4F07F9495F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:to="loc_us-gaap_StatementTable_73E105CA1C59A2BF46E65B4F07F9495F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_333FF869B1A368F387575B4F07F962BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_73E105CA1C59A2BF46E65B4F07F9495F" xlink:to="loc_us-gaap_StatementScenarioAxis_333FF869B1A368F387575B4F07F962BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DDFA78DDC5B550B3924A5B4F07F9E7C9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_333FF869B1A368F387575B4F07F962BB" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DDFA78DDC5B550B3924A5B4F07F9E7C9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DDFA78DDC5B550B3924A5B4F07F9E7C9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_333FF869B1A368F387575B4F07F962BB" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DDFA78DDC5B550B3924A5B4F07F9E7C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_CF74B651F28E6C6FCA555B4F07F90003" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_CF74B651F28E6C6FCA555B4F07F90003" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax_D9216587E0FA3816570A5B4F07F966F5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax_D9216587E0FA3816570A5B4F07F966F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_0FA50CDF001EF95F69545B4F07F965E4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_0FA50CDF001EF95F69545B4F07F965E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax_01CCE1674A44B32879F85B4F07F97C23" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_A33E6D51280C6B8404365B4F07F94808" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax_01CCE1674A44B32879F85B4F07F97C23" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ConsolidatedStatementsOfIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_17160FC6EA32E50C39E80803C057A9CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_StatementTable_17160FC6EA32E50C39E80803C057A9CE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_6A3AE7BD2154FB5B8E590803C0577B37" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_17160FC6EA32E50C39E80803C057A9CE" xlink:to="loc_us-gaap_StatementScenarioAxis_6A3AE7BD2154FB5B8E590803C0577B37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_37CCDF80C0DADAF2D9210803C057D808_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_6A3AE7BD2154FB5B8E590803C0577B37" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_37CCDF80C0DADAF2D9210803C057D808_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_37CCDF80C0DADAF2D9210803C057D808" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_6A3AE7BD2154FB5B8E590803C0577B37" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_37CCDF80C0DADAF2D9210803C057D808" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndDividendIncomeOperatingAbstract" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases" xlink:label="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_11A062DD249A83905BB10803C05788D7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:to="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_11A062DD249A83905BB10803C05788D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxable" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxable_2CD9F2616C57D8B6B3120803C057EBB2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxable_2CD9F2616C57D8B6B3120803C057EBB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_874109312352B6A085E80803C057E36B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_874109312352B6A085E80803C057E36B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_0B27FF66995AA80121FF0803C057D4DD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_0B27FF66995AA80121FF0803C057D4DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_DFF6AFDD2BCB843BBA670803C05731C4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_A37BDA8CA76D7D505FE90803C0570728" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_DFF6AFDD2BCB843BBA670803C05731C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseAbstract" xlink:label="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseDeposits" xlink:label="loc_us-gaap_InterestExpenseDeposits_9F91856415AB613407550803C057D6ED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:to="loc_us-gaap_InterestExpenseDeposits_9F91856415AB613407550803C057D6ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm" xlink:label="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm_A63B50F6BC36095046170803C057507F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:to="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm_A63B50F6BC36095046170803C057507F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_AE43248329565F0EAB480803C0573092" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_AE43248329565F0EAB480803C0573092" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseOtherShortTermBorrowings" xlink:label="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_3205BC9C08D356B152950803C057B07E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:to="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_3205BC9C08D356B152950803C057B07E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_92B8502BF0068CF4B9E50803C057D9F4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_28F3B3F383E733F775500803C0575B41" xlink:to="loc_us-gaap_InterestExpense_92B8502BF0068CF4B9E50803C057D9F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_AD49B55033F8E9AD7F8E0803C0570C88" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_AD49B55033F8E9AD7F8E0803C0570C88" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanAndLeaseLosses" xlink:label="loc_us-gaap_ProvisionForLoanAndLeaseLosses_AFA4120371BFA1CF4CE60803C057D1D5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_ProvisionForLoanAndLeaseLosses_AFA4120371BFA1CF4CE60803C057D1D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_31394B34D97CB80298E20803C057CB69" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_31394B34D97CB80298E20803C057CB69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeAbstract" xlink:label="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Depositaccountandtreasurymanagementfees" xlink:label="loc_colb_Depositaccountandtreasurymanagementfees_3D26180630A8259CE51C0803C05769E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Depositaccountandtreasurymanagementfees_3D26180630A8259CE51C0803C05769E0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Cardrevenue" xlink:label="loc_colb_Cardrevenue_596C08FC1BC7DC4DB0A00803C057C386" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Cardrevenue_596C08FC1BC7DC4DB0A00803C057C386" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Financialservicesandtrustrevenue" xlink:label="loc_colb_Financialservicesandtrustrevenue_B540E3116AFA62054AE00803C0574FC1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Financialservicesandtrustrevenue_B540E3116AFA62054AE00803C0574FC1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Loanrevenue" xlink:label="loc_colb_Loanrevenue_C7DEBB7B14D51A86667D0803C0578455" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Loanrevenue_C7DEBB7B14D51A86667D0803C0578455" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Merchantprocessingrevenue" xlink:label="loc_colb_Merchantprocessingrevenue_439B9EAE76AA1D64643D0803C0571C7C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Merchantprocessingrevenue_439B9EAE76AA1D64643D0803C0571C7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BankOwnedLifeInsuranceIncome" xlink:label="loc_us-gaap_BankOwnedLifeInsuranceIncome_0625CDD2CFCC3AB610090803C057FEDC" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_us-gaap_BankOwnedLifeInsuranceIncome_0625CDD2CFCC3AB610090803C057FEDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_CD2A645977208284EB530803C0573FD1" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_CD2A645977208284EB530803C0573FD1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Gainonsaleofmerchantcardservicesportfolio" xlink:label="loc_colb_Gainonsaleofmerchantcardservicesportfolio_E4BFA0BD989774456BDF0803C057B687" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_Gainonsaleofmerchantcardservicesportfolio_E4BFA0BD989774456BDF0803C057B687" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ChangeInFederalDepositInsuranceCorporationLossSharingAsset" xlink:label="loc_colb_ChangeInFederalDepositInsuranceCorporationLossSharingAsset_805175A564B9D4160E470803C057518D" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_colb_ChangeInFederalDepositInsuranceCorporationLossSharingAsset_805175A564B9D4160E470803C057518D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeOther" xlink:label="loc_us-gaap_NoninterestIncomeOther_3252E05173B0CCFAC1F30803C057C9AA" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_us-gaap_NoninterestIncomeOther_3252E05173B0CCFAC1F30803C057C9AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncome" xlink:label="loc_us-gaap_NoninterestIncome_A91D209431F45DFD2A030803C057F170" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_us-gaap_NoninterestIncome_A91D209431F45DFD2A030803C057F170" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestExpenseAbstract" xlink:label="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_67B375FAEFC91708E40D0803C057CE5B" xlink:to="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="loc_us-gaap_LaborAndRelatedExpense_3487F3FE683C698D29D60803C0577038" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_LaborAndRelatedExpense_3487F3FE683C698D29D60803C0577038" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OccupancyNet" xlink:label="loc_us-gaap_OccupancyNet_82CE22420588478727760803C0576533" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_OccupancyNet_82CE22420588478727760803C0576533" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_MerchantProcessing" xlink:label="loc_colb_MerchantProcessing_DF0DE7C352DBE6F9D8850803C0577CCE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_colb_MerchantProcessing_DF0DE7C352DBE6F9D8850803C0577CCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdvertisingExpense" xlink:label="loc_us-gaap_AdvertisingExpense_A4DCB337FB11CC3527C20803C05721A5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_AdvertisingExpense_A4DCB337FB11CC3527C20803C05721A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommunicationsAndInformationTechnology" xlink:label="loc_us-gaap_CommunicationsAndInformationTechnology_FF118CC43E83F5D052260803C0570015" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_CommunicationsAndInformationTechnology_FF118CC43E83F5D052260803C0570015" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProfessionalFees" xlink:label="loc_us-gaap_ProfessionalFees_6F028B5B61296AED5DFC0803C05767B2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_ProfessionalFees_6F028B5B61296AED5DFC0803C05767B2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TaxesLicensesAndFees" xlink:label="loc_colb_TaxesLicensesAndFees_CEFE6DD95567989CB5220803C0575148" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_colb_TaxesLicensesAndFees_CEFE6DD95567989CB5220803C0575148" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalDepositInsuranceCorporationPremiumExpense" xlink:label="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_BCF4FE47986241C5642D0803C067AA44" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_BCF4FE47986241C5642D0803C067AA44" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Netcostbenefitofoperationofotherrealestateowned" xlink:label="loc_colb_Netcostbenefitofoperationofotherrealestateowned_83E1BAC5F84B6D10F9B30803C0670CB8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_colb_Netcostbenefitofoperationofotherrealestateowned_83E1BAC5F84B6D10F9B30803C0670CB8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_DFAA3055BA97AE93E8B40803C06780BE" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_DFAA3055BA97AE93E8B40803C06780BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="loc_us-gaap_OtherNoninterestExpense_917396677542A5BC3F720803C0670B29" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_OtherNoninterestExpense_917396677542A5BC3F720803C0670B29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestExpense" xlink:label="loc_us-gaap_NoninterestExpense_AA69B7DB47DE606636E00803C06724C2" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_NoninterestExpense_AA69B7DB47DE606636E00803C06724C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_1177769759EC16558DF00803C0679B51" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_1177769759EC16558DF00803C0679B51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_051FA2C646138FC7F4850803C0671912" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_051FA2C646138FC7F4850803C0671912" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_292FB32DEED1AB3CAF340803C06722A6" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_7B27279B54CF98BA05410803C0570CFD" xlink:to="loc_us-gaap_NetIncomeLoss_292FB32DEED1AB3CAF340803C06722A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B96C83E311ED71614B40803C0571F96" xlink:to="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_C372C77470A435F3522C0803C0672909" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:to="loc_us-gaap_EarningsPerShareBasic_C372C77470A435F3522C0803C0672909" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_953502D9A38F2CC9ACDC0803C067BABB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:to="loc_us-gaap_EarningsPerShareDiluted_953502D9A38F2CC9ACDC0803C067BABB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_A3D2D8AC18E16A5EDB100803C067F4C4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_A3D2D8AC18E16A5EDB100803C067F4C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_8EDD1277877B0333B24B0803C0675182" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E34063873015D0940B610803C067BAEA" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_8EDD1277877B0333B24B0803C0675182" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/Deposits" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DepositsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DepositsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsetting" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingBalanceSheetOffsettingDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_BalanceSheetOffsettingLineItems" xlink:label="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BalanceSheetOffsettingTable" xlink:label="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4663E8EED0722C963CBEF28D83BB02A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4663E8EED0722C963CBEF28D83BB02A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_58072C1A2F2E02B24DB5F28D83BB7CF7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4663E8EED0722C963CBEF28D83BB02A3" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_58072C1A2F2E02B24DB5F28D83BB7CF7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_58072C1A2F2E02B24DB5F28D83BB7CF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4663E8EED0722C963CBEF28D83BB02A3" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_58072C1A2F2E02B24DB5F28D83BB7CF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember_B80F04490FC29B3DB1CAF28D83BBAB4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_58072C1A2F2E02B24DB5F28D83BB7CF7" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesMember_B80F04490FC29B3DB1CAF28D83BBAB4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_6F2C185DE6DD3ED65654F28D83BB7FBF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_6F2C185DE6DD3ED65654F28D83BB7FBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6F2C185DE6DD3ED65654F28D83BB7FBF" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6F2C185DE6DD3ED65654F28D83BB7FBF" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_09EEE06FD0A3CCAD8924F28D83BBC88A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782" xlink:to="loc_us-gaap_OtherAssetsMember_09EEE06FD0A3CCAD8924F28D83BBC88A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="loc_us-gaap_OtherLiabilitiesMember_18B58CEAE6D70AFE7B5AF28D83BBD77F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_D8FF26721B16C1579A50F28D83BBC782" xlink:to="loc_us-gaap_OtherLiabilitiesMember_18B58CEAE6D70AFE7B5AF28D83BBD77F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_D5ED0C93ED9E7AD9B5E3F28D83BB30B6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_D5ED0C93ED9E7AD9B5E3F28D83BB30B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_33E0095372B1F6FFD37DF28D83BB073F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D5ED0C93ED9E7AD9B5E3F28D83BB30B6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_33E0095372B1F6FFD37DF28D83BB073F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_33E0095372B1F6FFD37DF28D83BB073F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D5ED0C93ED9E7AD9B5E3F28D83BB30B6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_33E0095372B1F6FFD37DF28D83BB073F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_9179E4FDD504F1E9F83BF28D83BB50DD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_33E0095372B1F6FFD37DF28D83BB073F" xlink:to="loc_us-gaap_InterestRateContractMember_9179E4FDD504F1E9F83BF28D83BB50DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_E12D21F2809B29F5305DF28D83BB5412" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_BalanceSheetOffsettingTable_2849D9F534FEB9812422F28D83ACE7C6" xlink:to="loc_us-gaap_HedgingDesignationAxis_E12D21F2809B29F5305DF28D83BB5412" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_A4233C323EFFB262C330F28D83BB9965_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_E12D21F2809B29F5305DF28D83BB5412" xlink:to="loc_us-gaap_HedgingDesignationDomain_A4233C323EFFB262C330F28D83BB9965_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_A4233C323EFFB262C330F28D83BB9965" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_E12D21F2809B29F5305DF28D83BB5412" xlink:to="loc_us-gaap_HedgingDesignationDomain_A4233C323EFFB262C330F28D83BB9965" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount_1D76C06F7223FE0B344CF28D83BB1B3D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount_1D76C06F7223FE0B344CF28D83BB1B3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_71531024B14479FD9951F28D83BB4ED1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_71531024B14479FD9951F28D83BB4ED1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DerivativeAssetsGrossAmountsOffsetintheBalanceSheets" xlink:label="loc_colb_DerivativeAssetsGrossAmountsOffsetintheBalanceSheets_C0BBC5A7D5807652267FF28D83BBEA4D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_DerivativeAssetsGrossAmountsOffsetintheBalanceSheets_C0BBC5A7D5807652267FF28D83BBEA4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_EB0DBCF85F952440F89EF28D83BB8B32" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeAssets_EB0DBCF85F952440F89EF28D83BB8B32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeCollateralObligationToReturnSecurities" xlink:label="loc_us-gaap_DerivativeCollateralObligationToReturnSecurities_A622A520219573A9A19BF28D83BBE2C3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeCollateralObligationToReturnSecurities_A622A520219573A9A19BF28D83BBE2C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral_6E525FC89395DB6B7DF6F28D83BB0F98" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral_6E525FC89395DB6B7DF6F28D83BB0F98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_8D498596F9C50F66E3B6F28D83BBD614" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_8D498596F9C50F66E3B6F28D83BBD614" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DerivativeLiabilityGrossAmountsOffsetinBalanceSheets" xlink:label="loc_colb_DerivativeLiabilityGrossAmountsOffsetinBalanceSheets_6C41ECE3D5CE3A1893E2F28D83BBBD7C" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_DerivativeLiabilityGrossAmountsOffsetinBalanceSheets_6C41ECE3D5CE3A1893E2F28D83BBBD7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_E816203A52A9DAA9A988F28D83BB5207" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeLiabilities_E816203A52A9DAA9A988F28D83BB5207" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeCollateralRightToReclaimSecurities" xlink:label="loc_us-gaap_DerivativeCollateralRightToReclaimSecurities_5A295078D6CECCEB595DF28D83BBE7D5" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeCollateralRightToReclaimSecurities_5A295078D6CECCEB595DF28D83BBE7D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral_D1EE1A34AA04ED120D66F28D83BB88D7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral_D1EE1A34AA04ED120D66F28D83BB88D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross_4824D7655797A93B97A7F28D83BB02F0" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross_4824D7655797A93B97A7F28D83BB02F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Repurchaseagreementsamountsoffsetinbalancesheet" xlink:label="loc_colb_Repurchaseagreementsamountsoffsetinbalancesheet_2FE9FCFB5BE28D590FFBF28D83BB9642" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_Repurchaseagreementsamountsoffsetinbalancesheet_2FE9FCFB5BE28D590FFBF28D83BB9642" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Repurchaseagreementsnetamountpresentedinstatementoffinancialposition" xlink:label="loc_colb_Repurchaseagreementsnetamountpresentedinstatementoffinancialposition_CE6D63CE993BEB11289BF28D83BBF332" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_Repurchaseagreementsnetamountpresentedinstatementoffinancialposition_CE6D63CE993BEB11289BF28D83BBF332" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimSecurities" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimSecurities_7201C6DF301B92F37D0EF28D83BBD9B2" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimSecurities_7201C6DF301B92F37D0EF28D83BBD9B2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Securitiessoldunderagreementstorepurchaseamountnotoffset" xlink:label="loc_colb_Securitiessoldunderagreementstorepurchaseamountnotoffset_49F0E0050A599E14492DF28D83CB94AA" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_Securitiessoldunderagreementstorepurchaseamountnotoffset_49F0E0050A599E14492DF28D83CB94AA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount_6E00A856655F0B8C577FF28D83CB00E9" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount_6E00A856655F0B8C577FF28D83CB00E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement" xlink:label="loc_us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement_094662EA60EB163C7213F28D83BB68D0" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_BalanceSheetOffsettingLineItems_15C700439D022D89B575F28D83BB95B7" xlink:to="loc_us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement_094662EA60EB163C7213F28D83BB68D0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_DCBD5AEA47687C7CDF2406BF57314D89" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_DCBD5AEA47687C7CDF2406BF57314D89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4AD57499631B468E15B706BF5731A47F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_DCBD5AEA47687C7CDF2406BF57314D89" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4AD57499631B468E15B706BF5731A47F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4AD57499631B468E15B706BF5731A47F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_DCBD5AEA47687C7CDF2406BF57314D89" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4AD57499631B468E15B706BF5731A47F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember" xlink:label="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_D0A8D3A00457AFE4038406BF5731ABA8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4AD57499631B468E15B706BF5731A47F" xlink:to="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_D0A8D3A00457AFE4038406BF5731ABA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_EFE6AF6B55D9E1D4ABBD06BF5731821C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_EFE6AF6B55D9E1D4ABBD06BF5731821C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_EFE6AF6B55D9E1D4ABBD06BF5731821C" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_EFE6AF6B55D9E1D4ABBD06BF5731821C" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MaturityOvernightMember" xlink:label="loc_us-gaap_MaturityOvernightMember_00A525D01DCC58AFF1FE06BF5731D2E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:to="loc_us-gaap_MaturityOvernightMember_00A525D01DCC58AFF1FE06BF5731D2E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MaturityUpTo30DaysMember" xlink:label="loc_us-gaap_MaturityUpTo30DaysMember_6330079A6C62DF49576A06BF5731366F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:to="loc_us-gaap_MaturityUpTo30DaysMember_6330079A6C62DF49576A06BF5731366F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Maturity30To90DaysMember" xlink:label="loc_us-gaap_Maturity30To90DaysMember_BA4A3B9D014EEBE0AEB506BF573190EF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:to="loc_us-gaap_Maturity30To90DaysMember_BA4A3B9D014EEBE0AEB506BF573190EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MaturityOver90DaysMember" xlink:label="loc_us-gaap_MaturityOver90DaysMember_E2E39A00D7C1C6D89CBB06BF57311280" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_51558C8D7B8CCCA5EEF806BF5731EF8C" xlink:to="loc_us-gaap_MaturityOver90DaysMember_E2E39A00D7C1C6D89CBB06BF57311280" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_F2BCACB6B0F160453BEF06BF5731EDC4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_F2BCACB6B0F160453BEF06BF5731EDC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_A9E233C4F25ACF8593EC06BF5731DBBF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_F2BCACB6B0F160453BEF06BF5731EDC4" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_A9E233C4F25ACF8593EC06BF5731DBBF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_A9E233C4F25ACF8593EC06BF5731DBBF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_F2BCACB6B0F160453BEF06BF5731EDC4" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_A9E233C4F25ACF8593EC06BF5731DBBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_83F3F6010777E0CD892506BF5731194A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_HedgingDesignationAxis_83F3F6010777E0CD892506BF5731194A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_3F5EDD21F641107E1CCF06BF57316B63_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_83F3F6010777E0CD892506BF5731194A" xlink:to="loc_us-gaap_HedgingDesignationDomain_3F5EDD21F641107E1CCF06BF57316B63_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_3F5EDD21F641107E1CCF06BF57316B63" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_83F3F6010777E0CD892506BF5731194A" xlink:to="loc_us-gaap_HedgingDesignationDomain_3F5EDD21F641107E1CCF06BF57316B63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_54F8BD1709C0799BBBE206BF5731AD42" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_3F5EDD21F641107E1CCF06BF57316B63" xlink:to="loc_us-gaap_NondesignatedMember_54F8BD1709C0799BBBE206BF5731AD42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_5788E7674824A044D6EE06BF573124A9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_5788E7674824A044D6EE06BF573124A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_5788E7674824A044D6EE06BF573124A9" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_5788E7674824A044D6EE06BF573124A9" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_694DE3AEA0A23FEA280106BF57314BE7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242" xlink:to="loc_us-gaap_OtherAssetsMember_694DE3AEA0A23FEA280106BF57314BE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="loc_us-gaap_OtherLiabilitiesMember_C51CBE72EEC60E29D1FC06BF5731BAC0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8A0D075EE7BD0A22B96D06BF5731D242" xlink:to="loc_us-gaap_OtherLiabilitiesMember_C51CBE72EEC60E29D1FC06BF5731BAC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_0DCC5889A34AB1EA466B06BF57311357" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_44026A73011674B4BCA906BF5731CCD1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_0DCC5889A34AB1EA466B06BF57311357" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_C6457A33FC0757709B2406BF57317594_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0DCC5889A34AB1EA466B06BF57311357" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_C6457A33FC0757709B2406BF57317594_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_C6457A33FC0757709B2406BF57317594" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0DCC5889A34AB1EA466B06BF57311357" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_C6457A33FC0757709B2406BF57317594" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_0013E6C3DE952BEA05BE06BF5731EE39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_C6457A33FC0757709B2406BF57317594" xlink:to="loc_us-gaap_InterestRateContractMember_0013E6C3DE952BEA05BE06BF5731EE39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_FAD8B01ACABA48DD11B506BF573198C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_invest_DerivativeNotionalAmount_FAD8B01ACABA48DD11B506BF573198C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_6E02E3275485ED1753D806BF5731CF10" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_6E02E3275485ED1753D806BF5731CF10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_0A0E16F1FDB54048C90F06BF573153B2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_0A0E16F1FDB54048C90F06BF573153B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_E478F89377FE23CC6C5F06BF57314B08" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_E478F89377FE23CC6C5F06BF57314B08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement" xlink:label="loc_us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement_4E66436272121CB0A0C906BF57318461" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_SecuredBorrowingsGrossIncludingNotSubjectToMasterNettingArrangement_4E66436272121CB0A0C906BF57318461" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuredBorrowingsGrossDifferenceAmount" xlink:label="loc_us-gaap_SecuredBorrowingsGrossDifferenceAmount_C6DAB88C40499BD1E8EA06BF57310CEF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0B32EC1B427AA141E20106BF5731C6AA" xlink:to="loc_us-gaap_SecuredBorrowingsGrossDifferenceAmount_C6DAB88C40499BD1E8EA06BF57310CEF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DerivativesAndBalanceSheetOffsettingTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_451C80746B5A0CD2B73F5B4F0A3AEB6B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_79B0715CAD68EBD5D8EE5B4F0A3A94E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_451C80746B5A0CD2B73F5B4F0A3AEB6B" xlink:to="loc_us-gaap_DerivativeTable_79B0715CAD68EBD5D8EE5B4F0A3A94E8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4769B44AAF9F499F6CAA5B4F0A3A2C1B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_79B0715CAD68EBD5D8EE5B4F0A3A94E8" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4769B44AAF9F499F6CAA5B4F0A3A2C1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_5D0272A9CD572CBDBCEE5B4F0A3AB577_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4769B44AAF9F499F6CAA5B4F0A3A2C1B" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_5D0272A9CD572CBDBCEE5B4F0A3AB577_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_5D0272A9CD572CBDBCEE5B4F0A3AB577" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_4769B44AAF9F499F6CAA5B4F0A3A2C1B" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_5D0272A9CD572CBDBCEE5B4F0A3AB577" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember_40400AEE2D8620DA4BC55B4F0A3AF6CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_5D0272A9CD572CBDBCEE5B4F0A3AB577" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesMember_40400AEE2D8620DA4BC55B4F0A3AF6CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_D6DEA768B7269D7993BF5B4F0A3A4BB7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_79B0715CAD68EBD5D8EE5B4F0A3A94E8" xlink:to="loc_us-gaap_HedgingDesignationAxis_D6DEA768B7269D7993BF5B4F0A3A4BB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_579F213EB84F0EDF68315B4F0A3A48DF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_D6DEA768B7269D7993BF5B4F0A3A4BB7" xlink:to="loc_us-gaap_HedgingDesignationDomain_579F213EB84F0EDF68315B4F0A3A48DF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_579F213EB84F0EDF68315B4F0A3A48DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_D6DEA768B7269D7993BF5B4F0A3A4BB7" xlink:to="loc_us-gaap_HedgingDesignationDomain_579F213EB84F0EDF68315B4F0A3A48DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_AAF3EA1908E763816A225B4F0A3AB1AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_579F213EB84F0EDF68315B4F0A3A48DF" xlink:to="loc_us-gaap_NondesignatedMember_AAF3EA1908E763816A225B4F0A3AB1AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock" xlink:label="loc_us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_8A0F3332A35F156DC1565B4F0A3AFEAB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_451C80746B5A0CD2B73F5B4F0A3AEB6B" xlink:to="loc_us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_8A0F3332A35F156DC1565B4F0A3AFEAB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BalanceSheetOffsettingTableTextBlock" xlink:label="loc_colb_BalanceSheetOffsettingTableTextBlock_245218F65BE52C1F58A25B4F0A3ACD06" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_451C80746B5A0CD2B73F5B4F0A3AEB6B" xlink:to="loc_colb_BalanceSheetOffsettingTableTextBlock_245218F65BE52C1F58A25B4F0A3ACD06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock" xlink:label="loc_us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock_D62F61C66D019506767A5B4F0A3A3D57" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_451C80746B5A0CD2B73F5B4F0A3AEB6B" xlink:to="loc_us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock_D62F61C66D019506767A5B4F0A3A3D57" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentInformationLineItems" xlink:label="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:type="locator" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentInformationTable" xlink:label="loc_dei_DocumentInformationTable_74662E544BC7AC81A3C02BE7715934D1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_DocumentInformationTable_74662E544BC7AC81A3C02BE7715934D1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentInformationDocumentAxis" xlink:label="loc_dei_DocumentInformationDocumentAxis_D7E2B5599BD7F689ED322BE7715A013C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_74662E544BC7AC81A3C02BE7715934D1" xlink:to="loc_dei_DocumentInformationDocumentAxis_D7E2B5599BD7F689ED322BE7715A013C" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentDomain" xlink:label="loc_dei_DocumentDomain_9FD5DD1B25DC17F616692BE7715A2EE4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_DocumentInformationDocumentAxis_D7E2B5599BD7F689ED322BE7715A013C" xlink:to="loc_dei_DocumentDomain_9FD5DD1B25DC17F616692BE7715A2EE4_default" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentDomain" xlink:label="loc_dei_DocumentDomain_9FD5DD1B25DC17F616692BE7715A2EE4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_DocumentInformationDocumentAxis_D7E2B5599BD7F689ED322BE7715A013C" xlink:to="loc_dei_DocumentDomain_9FD5DD1B25DC17F616692BE7715A2EE4" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_B58CEDCAAE2248A32E1F2BE7715B636E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_DocumentType_B58CEDCAAE2248A32E1F2BE7715B636E" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_63BDB9403940D0CE7DCF2BE7715CB913" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_AmendmentFlag_63BDB9403940D0CE7DCF2BE7715CB913" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityEmergingGrowthCompany" xlink:label="loc_dei_EntityEmergingGrowthCompany_3CB8F149C07103272E5C2BE7715CE540" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityEmergingGrowthCompany_3CB8F149C07103272E5C2BE7715CE540" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityShellCompany" xlink:label="loc_dei_EntityShellCompany_38AFBC2ED9AEBC6FC9B02BE772BFA30D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityShellCompany_38AFBC2ED9AEBC6FC9B02BE772BFA30D" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntitySmallBusiness" xlink:label="loc_dei_EntitySmallBusiness_67C307802CF11864841A2BE7715C4CEC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntitySmallBusiness_67C307802CF11864841A2BE7715C4CEC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_EF6338676B49352DE2C62BE7715C894F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_DocumentPeriodEndDate_EF6338676B49352DE2C62BE7715C894F" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_EF722C4DC3339282E77C2BE7715C77DC" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_DocumentFiscalYearFocus_EF722C4DC3339282E77C2BE7715C77DC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_897195969C611462FEDC2BE7715CECAE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_DocumentFiscalPeriodFocus_897195969C611462FEDC2BE7715CECAE" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_97A21CEF08636B03067A2BE7715DCEA8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityRegistrantName_97A21CEF08636B03067A2BE7715DCEA8" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_0EAD2A8FBD41C2D947E02BE7715DECE4" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityCentralIndexKey_0EAD2A8FBD41C2D947E02BE7715DECE4" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_A3737108354B8596D1BB2BE7715DE9EC" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_CurrentFiscalYearEndDate_A3737108354B8596D1BB2BE7715DE9EC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_7EF42048CF7025F7BCCC2BE7715DC2E1" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityFilerCategory_7EF42048CF7025F7BCCC2BE7715DC2E1" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_24EB97D4CAB8AD963ECF2BE7715D19FC" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_24EB97D4CAB8AD963ECF2BE7715D19FC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_80DAA611B8FC5B87757D2BE7715D9141" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_80DAA611B8FC5B87757D2BE7715D9141" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityVoluntaryFilers" xlink:label="loc_dei_EntityVoluntaryFilers_FAAB0E64EC9C009912E62BE7715E9BBC" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityVoluntaryFilers_FAAB0E64EC9C009912E62BE7715E9BBC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_76AA9B79ED83B8D4DF462BE7715EDBED" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityCurrentReportingStatus_76AA9B79ED83B8D4DF462BE7715EDBED" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityPublicFloat" xlink:label="loc_dei_EntityPublicFloat_248234A96F5B31DECF442BE7715E3DAE" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_ED636D46D931E912D98A2BE7715B36B4" xlink:to="loc_dei_EntityPublicFloat_248234A96F5B31DECF442BE7715E3DAE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EarningsPerCommonShare" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EarningsPerCommonShareScheduleOfBasicAndDilutedEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareBasicLineItems" xlink:label="loc_us-gaap_EarningsPerShareBasicLineItems_E34972AE170A07640FD15B4F0A594471" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_C39D17A0101C657960095B4F0A596B6D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_E34972AE170A07640FD15B4F0A594471" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_C39D17A0101C657960095B4F0A596B6D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_574F2C50DE99B3FE44F65B4F0A5929D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_C39D17A0101C657960095B4F0A596B6D" xlink:to="loc_us-gaap_StatementClassOfStockAxis_574F2C50DE99B3FE44F65B4F0A5929D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_E1011FDF99C6325ACB6A5B4F0A5972D6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_574F2C50DE99B3FE44F65B4F0A5929D5" xlink:to="loc_us-gaap_ClassOfStockDomain_E1011FDF99C6325ACB6A5B4F0A5972D6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_E1011FDF99C6325ACB6A5B4F0A5972D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_574F2C50DE99B3FE44F65B4F0A5929D5" xlink:to="loc_us-gaap_ClassOfStockDomain_E1011FDF99C6325ACB6A5B4F0A5972D6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BasicEarningsAllocatedToCommonShareholders" xlink:label="loc_colb_BasicEarningsAllocatedToCommonShareholders_0855A0BB6FCB5FDFEFEA5B4F0A5949EB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_E34972AE170A07640FD15B4F0A594471" xlink:to="loc_colb_BasicEarningsAllocatedToCommonShareholders_0855A0BB6FCB5FDFEFEA5B4F0A5949EB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EarningsPerCommonShareTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EmployeeBenefitPlans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EmployeeBenefitPlansDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitLineItems" xlink:label="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_0D9D0992259374B6692F06BF57020938" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_0D9D0992259374B6692F06BF57020938" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitAxis" xlink:label="loc_colb_EmployeeBenefitAxis_7302B88A9FBCF5C8878D06BF570275BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_0D9D0992259374B6692F06BF57020938" xlink:to="loc_colb_EmployeeBenefitAxis_7302B88A9FBCF5C8878D06BF570275BB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitDomain" xlink:label="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_EmployeeBenefitAxis_7302B88A9FBCF5C8878D06BF570275BB" xlink:to="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitDomain" xlink:label="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_EmployeeBenefitAxis_7302B88A9FBCF5C8878D06BF570275BB" xlink:to="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_867177E9837E3224D6B506BF5702718A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_867177E9837E3224D6B506BF5702718A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredProfitSharingMember" xlink:label="loc_us-gaap_DeferredProfitSharingMember_0A1B077BD5CC8BCF8E2606BF570227E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:to="loc_us-gaap_DeferredProfitSharingMember_0A1B077BD5CC8BCF8E2606BF570227E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_439955139C653600428106BF5702578A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:to="loc_us-gaap_EmployeeStockMember_439955139C653600428106BF5702578A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember" xlink:label="loc_us-gaap_OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember_5C5FE5ED825209139F0A06BF57029DF3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:to="loc_us-gaap_OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember_5C5FE5ED825209139F0A06BF57029DF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember" xlink:label="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_5309603FBA26876A656106BF57020E84" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_0A9C2E2220812ADE291806BF5702B815" xlink:to="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_5309603FBA26876A656106BF57020E84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_4A19F5E7FD83010998C106BF5702692D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_0D9D0992259374B6692F06BF57020938" xlink:to="loc_srt_RangeAxis_4A19F5E7FD83010998C106BF5702692D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4A19F5E7FD83010998C106BF5702692D" xlink:to="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4A19F5E7FD83010998C106BF5702692D" xlink:to="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_6A03E58E204CC60CBABF06BF57024CC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0" xlink:to="loc_srt_MinimumMember_6A03E58E204CC60CBABF06BF57024CC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_F6634811D672A4387CB206BF5702FBCC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5CC5B541FEE3B0BAC7C906BF5702A9C0" xlink:to="loc_srt_MaximumMember_F6634811D672A4387CB206BF5702FBCC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualEligibleAge" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualEligibleAge_5E6834E7115E20042E5406BF5702044A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualEligibleAge_5E6834E7115E20042E5406BF5702044A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_82E5DB5AA02B47D69CAE06BF5702C1CE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_82E5DB5AA02B47D69CAE06BF5702C1CE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualContributionToPlanByEmployeePercentOfEligibleCompensation" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualContributionToPlanByEmployeePercentOfEligibleCompensation_933E26A0A6DB6DF0D88206BF5702AF3C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualContributionToPlanByEmployeePercentOfEligibleCompensation_933E26A0A6DB6DF0D88206BF5702AF3C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualContributionRequirementsMatchingPercent" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualContributionRequirementsMatchingPercent_F92FB78882314E7C34F406BF5702ABAF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualContributionRequirementsMatchingPercent_F92FB78882314E7C34F406BF5702ABAF" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualContributionRequirementsPercentOfEachEmployeeCompensation" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualContributionRequirementsPercentOfEachEmployeeCompensation_62A9C9DB111E2516D1D306BF5702C8C5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualContributionRequirementsPercentOfEachEmployeeCompensation_62A9C9DB111E2516D1D306BF5702C8C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer_A0141F45CFF060976CC606BF570281C3" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer_A0141F45CFF060976CC606BF570281C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_3E245C5B1576394148A006BF5702728D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_3E245C5B1576394148A006BF5702728D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfLookBackPeriodUnderEmployeeStockPurchasePlan" xlink:label="loc_colb_NumberOfLookBackPeriodUnderEmployeeStockPurchasePlan_9EB99A1F1BEB7949C4B806BF570281FA" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_NumberOfLookBackPeriodUnderEmployeeStockPurchasePlan_9EB99A1F1BEB7949C4B806BF570281FA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LookBackPeriodUnderEmployeeStockPurchasePlan" xlink:label="loc_colb_LookBackPeriodUnderEmployeeStockPurchasePlan_520ACD084E3388E357A306BF57020F9B" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_LookBackPeriodUnderEmployeeStockPurchasePlan_520ACD084E3388E357A306BF57020F9B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DiscountOnCommonStockUnderEmployeeStockPurchasePlanPercent" xlink:label="loc_colb_DiscountOnCommonStockUnderEmployeeStockPurchasePlanPercent_36D6F1CE90F5B6662D4606BF57029366" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DiscountOnCommonStockUnderEmployeeStockPurchasePlanPercent_36D6F1CE90F5B6662D4606BF57029366" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_B012CEB4B776EDAF531C06BF5702B314" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_B012CEB4B776EDAF531C06BF5702B314" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_3192DA4B6F208273785006BF570230AD" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_3192DA4B6F208273785006BF570230AD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SharesAvailableForPurchaseUnderEmployeeStockPurchasePlan" xlink:label="loc_colb_SharesAvailableForPurchaseUnderEmployeeStockPurchasePlan_A611D63A4217EC1C1BB106BF57020E61" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_SharesAvailableForPurchaseUnderEmployeeStockPurchasePlan_A611D63A4217EC1C1BB106BF57020E61" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualVestingPeriod" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualVestingPeriod_C986E1588F9FB78EB79A06BF5702BA79" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualVestingPeriod_C986E1588F9FB78EB79A06BF5702BA79" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DeferredCompensationArrangementWithIndividualBenefitPeriod" xlink:label="loc_colb_DeferredCompensationArrangementWithIndividualBenefitPeriod_61A3DF912C56AE5B214E06BF570226D2" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DeferredCompensationArrangementWithIndividualBenefitPeriod_61A3DF912C56AE5B214E06BF570226D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability_4031EA5456B005705E9B06BF570256CF" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability_4031EA5456B005705E9B06BF570256CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_83AAAB6A80990A28434D06BF5702A6F8" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_83AAAB6A80990A28434D06BF5702A6F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_422BEA6EE26AA081A32E06BF57029881" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_422BEA6EE26AA081A32E06BF57029881" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationNormalRetirementAge" xlink:label="loc_colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationNormalRetirementAge_07D506F5FD0BC08512D906BF57024F21" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationNormalRetirementAge_07D506F5FD0BC08512D906BF57024F21" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationAnnualCostOfLivingBenefitAdjustment" xlink:label="loc_colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationAnnualCostOfLivingBenefitAdjustment_A79A103A2473464D812206BF5702201E" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_colb_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationAnnualCostOfLivingBenefitAdjustment_A79A103A2473464D812206BF5702201E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_7EEF991C2F3268FCF73606BF57028455" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_7EEF991C2F3268FCF73606BF57028455" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_CF25D0BB586728F5530C06BF5702242C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_CF25D0BB586728F5530C06BF5702242C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAmendments" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAmendments_A8B89C03350AE81A548F06BF5702FFC9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAmendments_A8B89C03350AE81A548F06BF5702FFC9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_FEC121DEDA68C7BA74C706BF5712833E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_FEC121DEDA68C7BA74C706BF5712833E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_BE67AC504B738B9741A106BF5712AF63" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_F539C3F9025B0121471F06BF57029562" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_BE67AC504B738B9741A106BF5712AF63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_104FD56F5C833C8D53C306BF5702FB33" xlink:to="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_F8B23B93AB2A43AD81AF06BF5712D603" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_F8B23B93AB2A43AD81AF06BF5712D603" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_A9076F785159016B55EB06BF57129F0F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_A9076F785159016B55EB06BF57129F0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_F25B6E4422560DA3415106BF5712FDA7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_F25B6E4422560DA3415106BF5712FDA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_75145C69DCFE0E235A8506BF571249F8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_75145C69DCFE0E235A8506BF571249F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_3A5CC5A9BF7D4F2DDADB06BF571264BC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_3A5CC5A9BF7D4F2DDADB06BF571264BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_996EEB3EFC6BF63C5E0206BF57124E0C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_996EEB3EFC6BF63C5E0206BF57124E0C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DefinedBenefitPlanExpectedFutureBenefitPayments" xlink:label="loc_colb_DefinedBenefitPlanExpectedFutureBenefitPayments_21B8F63FD581D141FAC106BF57122600" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_6A26015983D8C6BC89B406BF57126EE1" xlink:to="loc_colb_DefinedBenefitPlanExpectedFutureBenefitPayments_21B8F63FD581D141FAC106BF57122600" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/EmployeeBenefitPlansTables" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitLineItems" xlink:label="loc_colb_EmployeeBenefitLineItems_029C280296075F4823BB5B4F096FAB39" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_B24E1E1F96A1AA25EAFF5B4F096F6FED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_EmployeeBenefitLineItems_029C280296075F4823BB5B4F096FAB39" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_B24E1E1F96A1AA25EAFF5B4F096F6FED" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitAxis" xlink:label="loc_colb_EmployeeBenefitAxis_47DAF1109EF62338D9115B4F096FC403" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_B24E1E1F96A1AA25EAFF5B4F096F6FED" xlink:to="loc_colb_EmployeeBenefitAxis_47DAF1109EF62338D9115B4F096FC403" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitDomain" xlink:label="loc_colb_EmployeeBenefitDomain_996DEF43898D60E25DA25B4F096FAFD5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_EmployeeBenefitAxis_47DAF1109EF62338D9115B4F096FC403" xlink:to="loc_colb_EmployeeBenefitDomain_996DEF43898D60E25DA25B4F096FAFD5_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_EmployeeBenefitDomain" xlink:label="loc_colb_EmployeeBenefitDomain_996DEF43898D60E25DA25B4F096FAFD5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_EmployeeBenefitAxis_47DAF1109EF62338D9115B4F096FC403" xlink:to="loc_colb_EmployeeBenefitDomain_996DEF43898D60E25DA25B4F096FAFD5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember" xlink:label="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_D16A3A53277905C34CB95B4F096F68FF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitDomain_996DEF43898D60E25DA25B4F096FAFD5" xlink:to="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_D16A3A53277905C34CB95B4F096F68FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccumulatedAndProjectedBenefitObligationsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccumulatedAndProjectedBenefitObligationsTableTextBlock_41763CA90DCDEE5EF8A35B4F096FE40B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_029C280296075F4823BB5B4F096FAB39" xlink:to="loc_us-gaap_ScheduleOfAccumulatedAndProjectedBenefitObligationsTableTextBlock_41763CA90DCDEE5EF8A35B4F096FE40B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_423A289FCE2BAF454E715B4F096FFC0E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_EmployeeBenefitLineItems_029C280296075F4823BB5B4F096FAB39" xlink:to="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_423A289FCE2BAF454E715B4F096FFC0E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurement" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementCarryingAmountsAndEstimatedFairValuesOfSelectedFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D552C408D598AB8FE26506BF561E34B5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_A4FDA35D803405FBCA7106BF561A29A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D552C408D598AB8FE26506BF561E34B5" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_A4FDA35D803405FBCA7106BF561A29A3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_B97D9E7886EB06108BEE06BF561BB6C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_A4FDA35D803405FBCA7106BF561A29A3" xlink:to="loc_us-gaap_FinancialInstrumentAxis_B97D9E7886EB06108BEE06BF561BB6C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_427B2C4DABEF56CD693A06BF561BD451_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_B97D9E7886EB06108BEE06BF561BB6C1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_427B2C4DABEF56CD693A06BF561BD451_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_427B2C4DABEF56CD693A06BF561BD451" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_B97D9E7886EB06108BEE06BF561BB6C1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_427B2C4DABEF56CD693A06BF561BD451" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A55FA49529602FDBA73706BF561B821F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_A4FDA35D803405FBCA7106BF561A29A3" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A55FA49529602FDBA73706BF561B821F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A55FA49529602FDBA73706BF561B821F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A55FA49529602FDBA73706BF561B821F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_20CE8D526B22B7E1028606BF561C1FAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_20CE8D526B22B7E1028606BF561C1FAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_98FC669779FE59DDC55B06BF561CDD51" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_98FC669779FE59DDC55B06BF561CDD51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_9C65AA171B07F9DB25F106BF561C0541" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_76547EC6D6373E7AD0C806BF561B0E4A" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_9C65AA171B07F9DB25F106BF561C0541" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_DA92CED5EB55ECBAD66F06BF561CDE2A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_A4FDA35D803405FBCA7106BF561A29A3" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_DA92CED5EB55ECBAD66F06BF561CDE2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C1CDDCF736EF2BE186206BF561DB1E4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_DA92CED5EB55ECBAD66F06BF561CDE2A" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C1CDDCF736EF2BE186206BF561DB1E4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_640CE48623D882DB558606BF561C16EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_DA92CED5EB55ECBAD66F06BF561CDE2A" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_640CE48623D882DB558606BF561C16EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C1CDDCF736EF2BE186206BF561DB1E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_640CE48623D882DB558606BF561C16EC" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C1CDDCF736EF2BE186206BF561DB1E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_4C713255082D0EC0293406BF561DB6F3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_640CE48623D882DB558606BF561C16EC" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_4C713255082D0EC0293406BF561DB6F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_88507EFCBFC072C7B39506BF561DA6F8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_640CE48623D882DB558606BF561C16EC" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_88507EFCBFC072C7B39506BF561DA6F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D552C408D598AB8FE26506BF561E34B5" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_9B6C57CBD43291DAB0EB06BF561E67AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_9B6C57CBD43291DAB0EB06BF561E67AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="loc_us-gaap_InterestBearingDepositsInBanks_EB7DAE542345451FDF1706BF561F9A26" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_InterestBearingDepositsInBanks_EB7DAE542345451FDF1706BF561F9A26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_90B4DDECC5212CD291AD06BF561F7409" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_90B4DDECC5212CD291AD06BF561F7409" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_713BC8CB62287EFA7F3306BF561F45E5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_713BC8CB62287EFA7F3306BF561F45E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure" xlink:label="loc_us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_BC4A750B06F51992F24F06BF561F8313" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_BC4A750B06F51992F24F06BF561F8313" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure" xlink:label="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_086EF390FD445B1CF92706BF561F56F8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_086EF390FD445B1CF92706BF561F56F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_9E29BA1086B4BA96171406BF561F0F5F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_9E29BA1086B4BA96171406BF561F0F5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_029D6D0EDB31FDBD964906BF56207803" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_B2B940488A75732B807706BF561E375C" xlink:to="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_029D6D0EDB31FDBD964906BF56207803" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D552C408D598AB8FE26506BF561E34B5" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsFairValueDisclosure" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_0A66202C2D6E508E951406BF5620A0DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_0A66202C2D6E508E951406BF5620A0DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_381B2AB13F12C44454E506BF56208E7A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_381B2AB13F12C44454E506BF56208E7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure" xlink:label="loc_us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_6B6637F6F4C178C6603A06BF5620641A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_6B6637F6F4C178C6603A06BF5620641A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_77648951062877A1B9BE06BF56213DAF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_77648951062877A1B9BE06BF56213DAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_3D25CFF539C941A1BD4806BF5621E94D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_3D25CFF539C941A1BD4806BF5621E94D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_00DF676B1A7A9E1BE7C206BF5621015A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_C9A50C7A72E0AD4A8D2A06BF56201E04" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_00DF676B1A7A9E1BE7C206BF5621015A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementFinancialAssetsAccountedForFairValueOnNonrecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_131CAEDD00B98613F26DBA402D39BCA0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_131CAEDD00B98613F26DBA402D39BCA0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_7FD1FE1003C1B52ED55FBA402D39C965" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_131CAEDD00B98613F26DBA402D39BCA0" xlink:to="loc_us-gaap_FinancialInstrumentAxis_7FD1FE1003C1B52ED55FBA402D39C965" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_7FD1FE1003C1B52ED55FBA402D39C965" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_7FD1FE1003C1B52ED55FBA402D39C965" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansMember" xlink:label="loc_colb_ImpairedLoansMember_5232AAB468E99BC5A879BA402D3C93D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556" xlink:to="loc_colb_ImpairedLoansMember_5232AAB468E99BC5A879BA402D3C93D6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedMember" xlink:label="loc_colb_OtherRealEstateOwnedMember_37F026CE2A227FF5665BBA402D3C2F56" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B2771C1BE8B2ADC79E63BA402D394556" xlink:to="loc_colb_OtherRealEstateOwnedMember_37F026CE2A227FF5665BBA402D3C2F56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_067809D13C79D69CA065BA402D3CF5C9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_131CAEDD00B98613F26DBA402D39BCA0" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_067809D13C79D69CA065BA402D3CF5C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_067809D13C79D69CA065BA402D3CF5C9" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_067809D13C79D69CA065BA402D3CF5C9" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_E548B7F5B77EFB82A6B4BA402D3CE2B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_E548B7F5B77EFB82A6B4BA402D3CE2B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_3104EC89AC37E46F40BABA402D3CB1C2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_3104EC89AC37E46F40BABA402D3CB1C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_8D61A6A8B4D3EAD61978BA402D3C25D4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19A984D942B39DB845AFBA402D3C1614" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_8D61A6A8B4D3EAD61978BA402D3C25D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_85E2794CD9651CFE8CB6BA402D3C2348" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_131CAEDD00B98613F26DBA402D39BCA0" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_85E2794CD9651CFE8CB6BA402D3C2348" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_E6D427595E93EF426613BA402D3C9EDB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_85E2794CD9651CFE8CB6BA402D3C2348" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_E6D427595E93EF426613BA402D3C9EDB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_E6D427595E93EF426613BA402D3C9EDB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_85E2794CD9651CFE8CB6BA402D3C2348" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_E6D427595E93EF426613BA402D3C9EDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_D619B50DF23161C8ED30BA402D3C95CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_E6D427595E93EF426613BA402D3C9EDB" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_D619B50DF23161C8ED30BA402D3C95CE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansFinancialAssetsFairValue" xlink:label="loc_colb_ImpairedLoansFinancialAssetsFairValue_4C7075F39B1B2E795892BA402D3EE8CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_colb_ImpairedLoansFinancialAssetsFairValue_4C7075F39B1B2E795892BA402D3EE8CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:label="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_298E465178EC0E2B6EB0BA402D3ECF72" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_298E465178EC0E2B6EB0BA402D3ECF72" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedFairValue" xlink:label="loc_colb_OtherRealEstateOwnedFairValue_145763B4AEEAB42007D8BA402D3E2ADE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_colb_OtherRealEstateOwnedFairValue_145763B4AEEAB42007D8BA402D3E2ADE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedFairValueDisclosure" xlink:label="loc_colb_OtherRealEstateOwnedFairValueDisclosure_671B7C97EBF61D55A5F5BA402D3E1CF0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_colb_OtherRealEstateOwnedFairValueDisclosure_671B7C97EBF61D55A5F5BA402D3E1CF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_F711DC0DEA9551F38A40BA402D3E65E3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6943BD35872057B8883BBA402D3E0476" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_F711DC0DEA9551F38A40BA402D3E65E3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementFinancialAssetsAndLiabilitiesAccountedForFairValueOnRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E58F7B57AA70DACB2C9B06BF56653047" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E58F7B57AA70DACB2C9B06BF56653047" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_B754268AD9DEB1A1523906BF5666CFC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E58F7B57AA70DACB2C9B06BF56653047" xlink:to="loc_us-gaap_FinancialInstrumentAxis_B754268AD9DEB1A1523906BF5666CFC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_B754268AD9DEB1A1523906BF5666CFC8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_B754268AD9DEB1A1523906BF5666CFC8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_2F445F5C300865F0005406BF5666A750" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_2F445F5C300865F0005406BF5666A750" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="loc_us-gaap_MunicipalBondsMember_3C4EB821BD10ADDBF30E06BF566CEFD1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:to="loc_us-gaap_MunicipalBondsMember_3C4EB821BD10ADDBF30E06BF566CEFD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_094629A88BA02DFDDD3806BF566CDAEA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_094629A88BA02DFDDD3806BF566CDAEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_9FAFB16716F41C97732606BF566C92D0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_9FAFB16716F41C97732606BF566C92D0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSecuritiesMember" xlink:label="loc_colb_OtherSecuritiesMember_188D5C360875503DC32906BF566CE8EC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9EDE05BF10A042D80BB106BF5666966B" xlink:to="loc_colb_OtherSecuritiesMember_188D5C360875503DC32906BF566CE8EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E1DB6DE3CD9CE58C387406BF566CC928" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E58F7B57AA70DACB2C9B06BF56653047" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E1DB6DE3CD9CE58C387406BF566CC928" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E1DB6DE3CD9CE58C387406BF566CC928" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E1DB6DE3CD9CE58C387406BF566CC928" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_8A15AF8474591FEFCE1306BF566D9337" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_8A15AF8474591FEFCE1306BF566D9337" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_37BECA7F849580FD3BDD06BF566DFE30" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_37BECA7F849580FD3BDD06BF566DFE30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_38AC2D3977D04B7BCDE506BF566D7C9C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7E1A0CF9F17B974B6BEB06BF566CAA11" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_38AC2D3977D04B7BCDE506BF566D7C9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_41B3A880E6B5357803FB06BF566DD572" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E58F7B57AA70DACB2C9B06BF56653047" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_41B3A880E6B5357803FB06BF566DD572" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_23BD74B67CFBABFDD09B06BF566D0F70_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_41B3A880E6B5357803FB06BF566DD572" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_23BD74B67CFBABFDD09B06BF566D0F70_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_23BD74B67CFBABFDD09B06BF566D0F70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_41B3A880E6B5357803FB06BF566DD572" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_23BD74B67CFBABFDD09B06BF566D0F70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_3F887890882DEC91DA8D06BF566EEAC0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_23BD74B67CFBABFDD09B06BF566D0F70" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_3F887890882DEC91DA8D06BF566EEAC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueLiabilitiesLevel2ToLevel1TransfersDescription" xlink:label="loc_us-gaap_FairValueLiabilitiesLevel2ToLevel1TransfersDescription_6C77F2A781A5D7A84F7106BF566E8E8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_FairValueLiabilitiesLevel2ToLevel1TransfersDescription_6C77F2A781A5D7A84F7106BF566E8E8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecurities_CD5FDB6018867BCF86C806BF566F24B1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_AvailableForSaleSecurities_CD5FDB6018867BCF86C806BF566F24B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_B286168D6F1459129F3906BF566F9DEC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_B286168D6F1459129F3906BF566F9DEC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_C0FB5C8845CBE3D01CD606BF566F84C3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue_C0FB5C8845CBE3D01CD606BF566F84C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_8F8AB7AD4DC04F372E3606BF566FA149" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_F8E35075234B0002A4A206BF566EB98C" xlink:to="loc_us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_8F8AB7AD4DC04F372E3606BF566FA149" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementQuantitativeInformationAboutLevel3FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputTypeAxis" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_D3413AB1BC846A3EB9D306BF563B4DCD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_D3413AB1BC846A3EB9D306BF563B4DCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_5C5F8DCCE47DAA83C8A706BF563B858C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_D3413AB1BC846A3EB9D306BF563B4DCD" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_5C5F8DCCE47DAA83C8A706BF563B858C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_5C5F8DCCE47DAA83C8A706BF563B858C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_D3413AB1BC846A3EB9D306BF563B4DCD" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_5C5F8DCCE47DAA83C8A706BF563B858C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ReceivableByCollateralTypeAxis" xlink:label="loc_colb_ReceivableByCollateralTypeAxis_5CAD410E3721864974CF06BF563B9A58" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_colb_ReceivableByCollateralTypeAxis_5CAD410E3721864974CF06BF563B9A58" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ReceivableByCollateralTypeDomain" xlink:label="loc_colb_ReceivableByCollateralTypeDomain_4BECC536F9CCFE45525D06BF563B3A80_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_ReceivableByCollateralTypeAxis_5CAD410E3721864974CF06BF563B9A58" xlink:to="loc_colb_ReceivableByCollateralTypeDomain_4BECC536F9CCFE45525D06BF563B3A80_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ReceivableByCollateralTypeDomain" xlink:label="loc_colb_ReceivableByCollateralTypeDomain_4BECC536F9CCFE45525D06BF563B3A80" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_ReceivableByCollateralTypeAxis_5CAD410E3721864974CF06BF563B9A58" xlink:to="loc_colb_ReceivableByCollateralTypeDomain_4BECC536F9CCFE45525D06BF563B3A80" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralAxis" xlink:label="loc_us-gaap_CollateralAxis_0287456C4B7F6E4B2F8506BF563C5B55" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_CollateralAxis_0287456C4B7F6E4B2F8506BF563C5B55" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_0287456C4B7F6E4B2F8506BF563C5B55" xlink:to="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_0287456C4B7F6E4B2F8506BF563C5B55" xlink:to="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UncollateralizedMember" xlink:label="loc_us-gaap_UncollateralizedMember_B061D41E4DF3CB69222B0700E9396C60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067" xlink:to="loc_us-gaap_UncollateralizedMember_B061D41E4DF3CB69222B0700E9396C60" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CollateralDependentMember" xlink:label="loc_colb_CollateralDependentMember_14B3D5DFE66DE36BBE4F06BF563CEED8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067" xlink:to="loc_colb_CollateralDependentMember_14B3D5DFE66DE36BBE4F06BF563CEED8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NotCollateralDependentMember" xlink:label="loc_colb_NotCollateralDependentMember_25BFCFA7E4FA81F44F6E06BF563CC8C7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_6FD8B57E812A0609806A06BF563C2067" xlink:to="loc_colb_NotCollateralDependentMember_25BFCFA7E4FA81F44F6E06BF563CC8C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ValuationTechniqueAxis" xlink:label="loc_us-gaap_ValuationTechniqueAxis_8338A0A120CA9A14D29306BF563D886D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_ValuationTechniqueAxis_8338A0A120CA9A14D29306BF563D886D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_0E599CD17AF9B56F432606BF563D6727_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_8338A0A120CA9A14D29306BF563D886D" xlink:to="loc_us-gaap_ValuationTechniqueDomain_0E599CD17AF9B56F432606BF563D6727_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="loc_us-gaap_ValuationTechniqueDomain_0E599CD17AF9B56F432606BF563D6727" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_8338A0A120CA9A14D29306BF563D886D" xlink:to="loc_us-gaap_ValuationTechniqueDomain_0E599CD17AF9B56F432606BF563D6727" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MarketApproachValuationTechniqueMember" xlink:label="loc_us-gaap_MarketApproachValuationTechniqueMember_4A2750186669FD1D98C506BF563D7CC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_0E599CD17AF9B56F432606BF563D6727" xlink:to="loc_us-gaap_MarketApproachValuationTechniqueMember_4A2750186669FD1D98C506BF563D7CC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_5B25C4EFB59D2ED7D91B06BF563E79D4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_FinancialInstrumentAxis_5B25C4EFB59D2ED7D91B06BF563E79D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5B25C4EFB59D2ED7D91B06BF563E79D4" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5B25C4EFB59D2ED7D91B06BF563E79D4" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansMember" xlink:label="loc_colb_ImpairedLoansMember_32181D2ABE64605AD62D06BF563E6790" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D" xlink:to="loc_colb_ImpairedLoansMember_32181D2ABE64605AD62D06BF563E6790" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedMember" xlink:label="loc_colb_OtherRealEstateOwnedMember_3CF30DE93450642651B206BF563E8D9C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0E52ADAEE829A7BD102C06BF563E0B8D" xlink:to="loc_colb_OtherRealEstateOwnedMember_3CF30DE93450642651B206BF563E8D9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_389C243EB3DA6754A8EA06BF563E14D2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_srt_RangeAxis_389C243EB3DA6754A8EA06BF563E14D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_389C243EB3DA6754A8EA06BF563E14D2" xlink:to="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_389C243EB3DA6754A8EA06BF563E14D2" xlink:to="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_5FCF54390E894C00AE6B06BF563F06BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798" xlink:to="loc_srt_MinimumMember_5FCF54390E894C00AE6B06BF563F06BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_D6ABE384CEBCC4D6B8C506BF563FB640" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798" xlink:to="loc_srt_MaximumMember_D6ABE384CEBCC4D6B8C506BF563FB640" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_WeightedAverageMember" xlink:label="loc_srt_WeightedAverageMember_2AD264CB96C8ACF34A9906BF5640437B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C4FA035957CDAED0F70B06BF563FF798" xlink:to="loc_srt_WeightedAverageMember_2AD264CB96C8ACF34A9906BF5640437B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF70F19B0C1C9D029EB306BF56407E60" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF70F19B0C1C9D029EB306BF56407E60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4C997734FD630A16E34706BF5640E45C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF70F19B0C1C9D029EB306BF56407E60" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4C997734FD630A16E34706BF5640E45C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4C997734FD630A16E34706BF5640E45C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AF70F19B0C1C9D029EB306BF56407E60" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4C997734FD630A16E34706BF5640E45C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_46DF535BBD8FCAFBE2E906BF5640A657" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4C997734FD630A16E34706BF5640E45C" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_46DF535BBD8FCAFBE2E906BF5640A657" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7F038143922EF416FBF906BF564035B3" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_30C1843370A14C05102806BF563A3C99" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7F038143922EF416FBF906BF564035B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_9A2C057AB3CC21744E1F06BF5641B89A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7F038143922EF416FBF906BF564035B3" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_9A2C057AB3CC21744E1F06BF5641B89A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_9A2C057AB3CC21744E1F06BF5641B89A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_7F038143922EF416FBF906BF564035B3" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_9A2C057AB3CC21744E1F06BF5641B89A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_A8E5F2003A9E24AF231A06BF56414EC5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_9A2C057AB3CC21744E1F06BF5641B89A" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_A8E5F2003A9E24AF231A06BF56414EC5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansFinancialAssetsFairValue" xlink:label="loc_colb_ImpairedLoansFinancialAssetsFairValue_AADDF261E226B8910FBA06BF56429504" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_colb_ImpairedLoansFinancialAssetsFairValue_AADDF261E226B8910FBA06BF56429504" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedFairValue" xlink:label="loc_colb_OtherRealEstateOwnedFairValue_49E3B485D8E9C043BA2206BF564220E3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_colb_OtherRealEstateOwnedFairValue_49E3B485D8E9C043BA2206BF564220E3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansMeasurementInput" xlink:label="loc_colb_ImpairedLoansMeasurementInput_7743DA33B504310C6F4706BF564230CC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_colb_ImpairedLoansMeasurementInput_7743DA33B504310C6F4706BF564230CC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedFairValueDisclosure" xlink:label="loc_colb_OtherRealEstateOwnedFairValueDisclosure_A66F7DE98A9A51C340D406BF56427DFC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_colb_OtherRealEstateOwnedFairValueDisclosure_A66F7DE98A9A51C340D406BF56427DFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:label="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_9E2E1239FFE52A05C23A06BF564200EF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_EF275D62A594E0FED0A906BF56419F90" xlink:to="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_9E2E1239FFE52A05C23A06BF564200EF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FairValueAccountingAndMeasurementTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8A6AF37B9EB271D5D319751000059639" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_24AAFCE497665FAA7277751000035338" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8A6AF37B9EB271D5D319751000059639" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_24AAFCE497665FAA7277751000035338" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D2698A48D016757409B275100004DE47" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_24AAFCE497665FAA7277751000035338" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D2698A48D016757409B275100004DE47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15F1E21331DDE9A0117F7510000459B0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D2698A48D016757409B275100004DE47" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15F1E21331DDE9A0117F7510000459B0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15F1E21331DDE9A0117F7510000459B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D2698A48D016757409B275100004DE47" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15F1E21331DDE9A0117F7510000459B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_28B3D58727F946234441751000045160" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15F1E21331DDE9A0117F7510000459B0" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_28B3D58727F946234441751000045160" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_BBA9ABD4EE2C334BE97B751000052D6F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_24AAFCE497665FAA7277751000035338" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_BBA9ABD4EE2C334BE97B751000052D6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_D6528DDEBEE6A4D1DA9775100005A9C4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_BBA9ABD4EE2C334BE97B751000052D6F" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_D6528DDEBEE6A4D1DA9775100005A9C4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_D6528DDEBEE6A4D1DA9775100005A9C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_BBA9ABD4EE2C334BE97B751000052D6F" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_D6528DDEBEE6A4D1DA9775100005A9C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_3A65D6C954A212C87EDA7510000580BF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_D6528DDEBEE6A4D1DA9775100005A9C4" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_3A65D6C954A212C87EDA7510000580BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock_00323ED8248F063A1BCF751000056C63" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8A6AF37B9EB271D5D319751000059639" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock_00323ED8248F063A1BCF751000056C63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_D3C31D989A178DA4A07575100006413E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8A6AF37B9EB271D5D319751000059639" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_D3C31D989A178DA4A07575100006413E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock_DB316E7794EE3F70E85675100006C3A6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8A6AF37B9EB271D5D319751000059639" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock_DB316E7794EE3F70E85675100006C3A6" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowings" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowingsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DebtInstrumentsTable" xlink:label="loc_colb_DebtInstrumentsTable_B7EF55D87A80CBCEC69407D77AF2FDEC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_colb_DebtInstrumentsTable_B7EF55D87A80CBCEC69407D77AF2FDEC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_6D3F8CD903128274223E07D77AF37B5D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_DebtInstrumentsTable_B7EF55D87A80CBCEC69407D77AF2FDEC" xlink:to="loc_us-gaap_DebtInstrumentAxis_6D3F8CD903128274223E07D77AF37B5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_FEB87539164410FF26C807D77AF30A89_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6D3F8CD903128274223E07D77AF37B5D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_FEB87539164410FF26C807D77AF30A89_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_FEB87539164410FF26C807D77AF30A89" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6D3F8CD903128274223E07D77AF37B5D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_FEB87539164410FF26C807D77AF30A89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalReserveBankAdvancesMember" xlink:label="loc_us-gaap_FederalReserveBankAdvancesMember_37A3719DD34059EBD6B907D77AF34DD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_FEB87539164410FF26C807D77AF30A89" xlink:to="loc_us-gaap_FederalReserveBankAdvancesMember_37A3719DD34059EBD6B907D77AF34DD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_64090BCF660F5C83C53A07D77AF47F53" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_DebtInstrumentsTable_B7EF55D87A80CBCEC69407D77AF2FDEC" xlink:to="loc_us-gaap_FinancialInstrumentAxis_64090BCF660F5C83C53A07D77AF47F53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_64090BCF660F5C83C53A07D77AF47F53" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_64090BCF660F5C83C53A07D77AF47F53" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableMember" xlink:label="loc_us-gaap_LoansReceivableMember_B32009B8C0621CF259C307D77AF4B30D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032" xlink:to="loc_us-gaap_LoansReceivableMember_B32009B8C0621CF259C307D77AF4B30D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialLoanMember" xlink:label="loc_us-gaap_CommercialLoanMember_5523FBB4F649FC4D18D807D77AF40B2F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_E5727D862873F3804C0407D77AF4B032" xlink:to="loc_us-gaap_CommercialLoanMember_5523FBB4F649FC4D18D807D77AF40B2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate_102DC9AFDD1BA0A1ABB907D77AF595BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate_102DC9AFDD1BA0A1ABB907D77AF595BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateUnderOneYear" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateUnderOneYear_3AE98FE691DAAA41DFA707D77AF543F9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateUnderOneYear_3AE98FE691DAAA41DFA707D77AF543F9" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToFiveYearsFromBalanceSheetDate" xlink:label="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToFiveYearsFromBalanceSheetDate_7FA483ED4B773DF591AE07D77AF53E78" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToFiveYearsFromBalanceSheetDate_7FA483ED4B773DF591AE07D77AF53E78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateOneToFiveYears" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateOneToFiveYears_796FF69CE6CCCE3D76D207D77AF6CE22" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateOneToFiveYears_796FF69CE6CCCE3D76D207D77AF6CE22" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateAfterTenYearsFromBalanceSheetDate" xlink:label="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateAfterTenYearsFromBalanceSheetDate_3CE0A205B54787D93BC407D77AF6BAE7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateAfterTenYearsFromBalanceSheetDate_3CE0A205B54787D93BC407D77AF6BAE7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateAfterTenYears" xlink:label="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateAfterTenYears_CB32297E5EDEDA41163B07D77AF66910" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateAfterTenYears_CB32297E5EDEDA41163B07D77AF66910" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateBeforeValuationAdjustment" xlink:label="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateBeforeValuationAdjustment_89D438C0188E1DBF246907D77AF6AFB0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_colb_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRateBeforeValuationAdjustment_89D438C0188E1DBF246907D77AF6AFB0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankFixedRateAdvancesValuationAdjustmentFromAcquisitionAccounting" xlink:label="loc_colb_FederalHomeLoanBankFixedRateAdvancesValuationAdjustmentFromAcquisitionAccounting_099AFA516E3A1E06D45307D77AF6149E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_colb_FederalHomeLoanBankFixedRateAdvancesValuationAdjustmentFromAcquisitionAccounting_099AFA516E3A1E06D45307D77AF6149E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRate" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRate_45C4B02D6FF7A4E616FF07D77AF6C01F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryAbstract_D61E8685E1B67B740EA707D77AF5F2C5" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryByInterestRateTypeFixedRate_45C4B02D6FF7A4E616FF07D77AF6C01F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesLongTerm" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_7E22FA497E39D1FDE1A907D77AF7C506" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_7E22FA497E39D1FDE1A907D77AF7C506" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding_8A94423702FA69D95D9A07D77AF75025" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding_8A94423702FA69D95D9A07D77AF75025" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd_AF2E289A641A3C174F4807D77AF7B08B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd_AF2E289A641A3C174F4807D77AF7B08B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear_FAF24FB15532E3019AC707D77AF83F4D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear_FAF24FB15532E3019AC707D77AF83F4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateAtPeriodEnd" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateAtPeriodEnd_1725DA51D92D868E612D07D77AF8087F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract_13694C1900D6467F797907D77AF787AB" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateAtPeriodEnd_1725DA51D92D868E612D07D77AF8087F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable_DE398A8B5ABF0831E71207D77AF8BA42" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable_DE398A8B5ABF0831E71207D77AF8BA42" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalReserveBankAdvancesActivityForYearAbstract" xlink:label="loc_colb_FederalReserveBankAdvancesActivityForYearAbstract_8E838E43854C93D0221A07D77AF87262" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_colb_FederalReserveBankAdvancesActivityForYearAbstract_8E838E43854C93D0221A07D77AF87262" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalReserveBankAdvancesActivityfortheyearaveragebalanceofagreementsoutstanding" xlink:label="loc_colb_FederalReserveBankAdvancesActivityfortheyearaveragebalanceofagreementsoutstanding_24BD2003955B061F989207D77AF82FAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_FederalReserveBankAdvancesActivityForYearAbstract_8E838E43854C93D0221A07D77AF87262" xlink:to="loc_colb_FederalReserveBankAdvancesActivityfortheyearaveragebalanceofagreementsoutstanding_24BD2003955B061F989207D77AF82FAC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalReserveBankAdvancesMaximumAmountAvailable" xlink:label="loc_colb_FederalReserveBankAdvancesMaximumAmountAvailable_1B4DCCB4F0DF68E3540807D77AF85994" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59C62259DBDEA0C4B2A007D77AF5BB85" xlink:to="loc_colb_FederalReserveBankAdvancesMaximumAmountAvailable_1B4DCCB4F0DF68E3540807D77AF85994" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/FederalHomeLoanBankAndFederalReserveBankBorrowingsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_55C97C896DCC6A1837F05B4F0A2A221E" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DebtInstrumentsTable" xlink:label="loc_colb_DebtInstrumentsTable_E0A01BBB3E278F2A4E3D5B4F0A2A34A6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55C97C896DCC6A1837F05B4F0A2A221E" xlink:to="loc_colb_DebtInstrumentsTable_E0A01BBB3E278F2A4E3D5B4F0A2A34A6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_418DD84ACFC85925F8C95B4F0A2AD2A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_DebtInstrumentsTable_E0A01BBB3E278F2A4E3D5B4F0A2A34A6" xlink:to="loc_us-gaap_DebtInstrumentAxis_418DD84ACFC85925F8C95B4F0A2AD2A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_418DD84ACFC85925F8C95B4F0A2AD2A7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_418DD84ACFC85925F8C95B4F0A2AD2A7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMember" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMember_7F9E4033BEF1AA2DB5625B4F0A2A7C9A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMember_7F9E4033BEF1AA2DB5625B4F0A2A7C9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalReserveBankAdvancesMember" xlink:label="loc_us-gaap_FederalReserveBankAdvancesMember_28720A5B6B0CF652774E5B4F0A2A96AD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_67D5DF223F3548BFA6BC5B4F0A2A7F38" xlink:to="loc_us-gaap_FederalReserveBankAdvancesMember_28720A5B6B0CF652774E5B4F0A2A96AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_8DCFDA4D9DC82DEB3C205B4F0A2AF5C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55C97C896DCC6A1837F05B4F0A2A221E" xlink:to="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_8DCFDA4D9DC82DEB3C205B4F0A2AF5C1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_DebtInstrumentActivityForYearTableTextBlock" xlink:label="loc_colb_DebtInstrumentActivityForYearTableTextBlock_927632B928038900A4CE5B4F0A2AE582" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55C97C896DCC6A1837F05B4F0A2A221E" xlink:to="loc_colb_DebtInstrumentActivityForYearTableTextBlock_927632B928038900A4CE5B4F0A2AE582" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock" xlink:label="loc_us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock_45D7970E1D99B118F2395B4F0A2ACBAE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55C97C896DCC6A1837F05B4F0A2A221E" xlink:to="loc_us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock_45D7970E1D99B118F2395B4F0A2ACBAE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/GoodwillAndIntangibleAssets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsLineItems" xlink:label="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsTable" xlink:label="loc_colb_GoodwillAndIntangibleAssetsTable_D571022279BDF3A997855B4F09FC7823" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:to="loc_colb_GoodwillAndIntangibleAssetsTable_D571022279BDF3A997855B4F09FC7823" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9A2CDD33ABB0E6FD6B865B4F09FC2C45" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_GoodwillAndIntangibleAssetsTable_D571022279BDF3A997855B4F09FC7823" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9A2CDD33ABB0E6FD6B865B4F09FC2C45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B915270AA031BD09C4145B4F09FCFA0B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9A2CDD33ABB0E6FD6B865B4F09FC2C45" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B915270AA031BD09C4145B4F09FCFA0B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B915270AA031BD09C4145B4F09FCFA0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9A2CDD33ABB0E6FD6B865B4F09FC2C45" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B915270AA031BD09C4145B4F09FCFA0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CoreDepositsMember" xlink:label="loc_us-gaap_CoreDepositsMember_593C05338927D78A6AE05B4F09FC668C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B915270AA031BD09C4145B4F09FCFA0B" xlink:to="loc_us-gaap_CoreDepositsMember_593C05338927D78A6AE05B4F09FC668C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_AEE75EB116C46A74B45D5B4F09FC8B4E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_AEE75EB116C46A74B45D5B4F09FC8B4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_C1A7BA4DB0197A3C61A85B4F09FC5140" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_C1A7BA4DB0197A3C61A85B4F09FC5140" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsRollForward" xlink:label="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:to="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_789EB204DFDD78C916CE5B4F09FC37AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_Goodwill_789EB204DFDD78C916CE5B4F09FC37AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_9D85940FF3F0FEAEE1605B4F09FC7C8C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_9D85940FF3F0FEAEE1605B4F09FC7C8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_3005CCC43C671F4513535B4F09FCF67C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_3005CCC43C671F4513535B4F09FCF67C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_50BF78A18A406DD2CF695B4F09FC8E10" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_50BF78A18A406DD2CF695B4F09FC8E10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_E142F392405C7DD77CA45B4F09FC2E0C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_E142F392405C7DD77CA45B4F09FC2E0C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_87B787FF61A980732CDC5B4F09FC250C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_87B787FF61A980732CDC5B4F09FC250C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_556CBAB4788425E2261D5B4F09FC7FD8" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_556CBAB4788425E2261D5B4F09FC7FD8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsTotal" xlink:label="loc_colb_GoodwillAndIntangibleAssetsTotal_2AF9DFA51AC8C0F84A7C5B4F09FCBCA2" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsRollForward_9A5197A834246F868E065B4F09FCE0A4" xlink:to="loc_colb_GoodwillAndIntangibleAssetsTotal_2AF9DFA51AC8C0F84A7C5B4F09FCBCA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_594FB31D9F0799A2295E5B4F09FCDC94" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_DA4CA00AD9EA66DF54AE5B4F09FCA0E6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_594FB31D9F0799A2295E5B4F09FCDC94" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsSummaryOfEstimatedFutureAmortizationExpenseOfCoreDepositIntangiblesDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsLineItems" xlink:label="loc_colb_GoodwillAndIntangibleAssetsLineItems_BBBA92CEE46473CAE47906BF579E8935" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_GoodwillAndIntangibleAssetsTable" xlink:label="loc_colb_GoodwillAndIntangibleAssetsTable_F845DA4119EC70AFC5AD06BF579EC33C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_BBBA92CEE46473CAE47906BF579E8935" xlink:to="loc_colb_GoodwillAndIntangibleAssetsTable_F845DA4119EC70AFC5AD06BF579EC33C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0E700527395B2A5E513206BF579ED1E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_GoodwillAndIntangibleAssetsTable_F845DA4119EC70AFC5AD06BF579EC33C" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0E700527395B2A5E513206BF579ED1E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2A37DD023E68E8C4D2C606BF579E0B01_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0E700527395B2A5E513206BF579ED1E3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2A37DD023E68E8C4D2C606BF579E0B01_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2A37DD023E68E8C4D2C606BF579E0B01" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_0E700527395B2A5E513206BF579ED1E3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2A37DD023E68E8C4D2C606BF579E0B01" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CoreDepositsMember" xlink:label="loc_us-gaap_CoreDepositsMember_191AB99D346A9CF3BB5F06BF579EC3CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2A37DD023E68E8C4D2C606BF579E0B01" xlink:to="loc_us-gaap_CoreDepositsMember_191AB99D346A9CF3BB5F06BF579EC3CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_GoodwillAndIntangibleAssetsLineItems_BBBA92CEE46473CAE47906BF579E8935" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_01F16E815457089EE1B506BF579EAE99" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_01F16E815457089EE1B506BF579EAE99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_B176A921650B6F3C8EB606BF579EF064" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_B176A921650B6F3C8EB606BF579EF064" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_CD9581D19FA424C3E24406BF579E182A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_CD9581D19FA424C3E24406BF579E182A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_59B725135252FB9CDEBB06BF579E5F09" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_59B725135252FB9CDEBB06BF579E5F09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_439DC9CED8869E63C04206BF579E0C7A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D1D9A68CEB0E7A4FBBEF06BF579E6575" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_439DC9CED8869E63C04206BF579E0C7A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/GoodwillAndIntangibleAssetsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/IncomeTax" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/IncomeTaxDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxContingencyLineItems" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxContingencyTable" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_BE19F2411457933DBDB2E920D68BBA15" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_BE19F2411457933DBDB2E920D68BBA15" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_E1AD365A047FD3304094E920D68B2AD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_BE19F2411457933DBDB2E920D68BBA15" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_E1AD365A047FD3304094E920D68B2AD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_B4F91420F3738F03F5FBE920D68B1ADC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_E1AD365A047FD3304094E920D68B2AD0" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_B4F91420F3738F03F5FBE920D68B1ADC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_B4F91420F3738F03F5FBE920D68B1ADC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_E1AD365A047FD3304094E920D68B2AD0" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_B4F91420F3738F03F5FBE920D68B1ADC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentFederalTaxExpenseBenefit_D0A0A3AEE7027F44E260E920D68B39F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_us-gaap_CurrentFederalTaxExpenseBenefit_D0A0A3AEE7027F44E260E920D68B39F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Federaloperatinglosscarryforwardssettobegintoexpirein2024" xlink:label="loc_colb_Federaloperatinglosscarryforwardssettobegintoexpirein2024_B6054151F7147E85CB2EE920D68B1109" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_colb_Federaloperatinglosscarryforwardssettobegintoexpirein2024_B6054151F7147E85CB2EE920D68B1109" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Idahostateoperatinglosscarryforwardssettobegintoexpirein2024" xlink:label="loc_colb_Idahostateoperatinglosscarryforwardssettobegintoexpirein2024_226F441F001684DE2736E920D68B626E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_colb_Idahostateoperatinglosscarryforwardssettobegintoexpirein2024_226F441F001684DE2736E920D68B626E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_F98D9F2BC8A05F54BA49E920D68B106E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_F98D9F2BC8A05F54BA49E920D68B106E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Oregonstateoperatinglosscarryforwardssettobegintoexpirein2024" xlink:label="loc_colb_Oregonstateoperatinglosscarryforwardssettobegintoexpirein2024_0E25132BD528419FC99AE920D68BDFE6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_colb_Oregonstateoperatinglosscarryforwardssettobegintoexpirein2024_0E25132BD528419FC99AE920D68BDFE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfDomesticSubsidiaries" xlink:label="loc_us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfDomesticSubsidiaries_DCA657EF89CC884FD88DE920D68B2F64" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_0BBD70A1C99F2C02E166E920D68B3D9C" xlink:to="loc_us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfDomesticSubsidiaries_DCA657EF89CC884FD88DE920D68B2F64" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/IncomeTaxTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/JuniorSubordinatedDebt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/JuniorSubordinatedDebtDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_JuniorsubordinateddebenturesLineItems" xlink:label="loc_colb_JuniorsubordinateddebenturesLineItems_DECB9BC00B9F5B291BCEA54E6C3EFD95" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_JuniorsubordinateddebenturesTable" xlink:label="loc_colb_JuniorsubordinateddebenturesTable_983A659A0B0BC20B3DABA54E6C3E6E81" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_JuniorsubordinateddebenturesLineItems_DECB9BC00B9F5B291BCEA54E6C3EFD95" xlink:to="loc_colb_JuniorsubordinateddebenturesTable_983A659A0B0BC20B3DABA54E6C3E6E81" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_BEB8BD2FB0E09F90384BA54E6C3E6841" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_JuniorsubordinateddebenturesTable_983A659A0B0BC20B3DABA54E6C3E6E81" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_BEB8BD2FB0E09F90384BA54E6C3E6841" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D38B876026F74208309FA54E6C3E82D2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_BEB8BD2FB0E09F90384BA54E6C3E6841" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D38B876026F74208309FA54E6C3E82D2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D38B876026F74208309FA54E6C3E82D2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_BEB8BD2FB0E09F90384BA54E6C3E6841" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D38B876026F74208309FA54E6C3E82D2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PacificContinentalMember" xlink:label="loc_colb_PacificContinentalMember_2A5299D5A188B4F893BBA54E6C3E5EDB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D38B876026F74208309FA54E6C3E82D2" xlink:to="loc_colb_PacificContinentalMember_2A5299D5A188B4F893BBA54E6C3E5EDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfSubordinatedDebt" xlink:label="loc_us-gaap_RepaymentsOfSubordinatedDebt_CD1E273A18E153530830A54E6C3EA3D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_JuniorsubordinateddebenturesLineItems_DECB9BC00B9F5B291BCEA54E6C3EFD95" xlink:to="loc_us-gaap_RepaymentsOfSubordinatedDebt_CD1E273A18E153530830A54E6C3EA3D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_JuniorSubordinatedNotes" xlink:label="loc_us-gaap_JuniorSubordinatedNotes_7ED995BE4BB8ED4BEFE1A54E6C3E3A44" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_JuniorsubordinateddebenturesLineItems_DECB9BC00B9F5B291BCEA54E6C3EFD95" xlink:to="loc_us-gaap_JuniorSubordinatedNotes_7ED995BE4BB8ED4BEFE1A54E6C3E3A44" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures" xlink:label="loc_colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures_C18AD46EBF358A7BBB6FA54E6C3ECED4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_JuniorsubordinateddebenturesLineItems_DECB9BC00B9F5B291BCEA54E6C3EFD95" xlink:to="loc_colb_BusinessCombinationPurchasePriceAllocationJuniorSubordinatedDebentures_C18AD46EBF358A7BBB6FA54E6C3ECED4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/JuniorSubordinatedDebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/Loans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansAnalysisOfAgedLoanPortfolioDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_661CC58750C06D8356315B4F0A4A00CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_661CC58750C06D8356315B4F0A4A00CA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_A299C1966FDF1E0DD6AE5B4F0A4A8341" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_661CC58750C06D8356315B4F0A4A00CA" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_A299C1966FDF1E0DD6AE5B4F0A4A8341" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_A299C1966FDF1E0DD6AE5B4F0A4A8341" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_A299C1966FDF1E0DD6AE5B4F0A4A8341" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_A2FFA38B16A989819A275B4F0A4A689F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_A2FFA38B16A989819A275B4F0A4A689F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_2B6CDD626F4207D2F03B5B4F0A4A0798" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_2B6CDD626F4207D2F03B5B4F0A4A0798" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_5912991E5A9117DDC1E15B4F0A4AB401" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_E5B19E187FB510E3BFC75B4F0A4A52DB" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_5912991E5A9117DDC1E15B4F0A4AB401" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_DF94A3FF106941E9424A5B4F0A4A23FD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_661CC58750C06D8356315B4F0A4A00CA" xlink:to="loc_colb_LoansByMajorCategoryAxis_DF94A3FF106941E9424A5B4F0A4A23FD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_43D8F01EAEA73307D3FF5B4F0A4A1D78_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_DF94A3FF106941E9424A5B4F0A4A23FD" xlink:to="loc_colb_LoansByMajorCategoryDomain_43D8F01EAEA73307D3FF5B4F0A4A1D78_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_43D8F01EAEA73307D3FF5B4F0A4A1D78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_DF94A3FF106941E9424A5B4F0A4A23FD" xlink:to="loc_colb_LoansByMajorCategoryDomain_43D8F01EAEA73307D3FF5B4F0A4A1D78" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_6BA830F2AD6880DAD9845B4F0A4A97B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_43D8F01EAEA73307D3FF5B4F0A4A1D78" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_6BA830F2AD6880DAD9845B4F0A4A97B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6ED03B573C14F6D4004C5B4F0A4AEF5C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_661CC58750C06D8356315B4F0A4A00CA" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6ED03B573C14F6D4004C5B4F0A4AEF5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6ED03B573C14F6D4004C5B4F0A4AEF5C" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6ED03B573C14F6D4004C5B4F0A4AEF5C" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_949B5841940958A9364C5B4F0A4A8F78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_949B5841940958A9364C5B4F0A4A8F78" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_0EC267DD362071635D005B4F0A4A0C73" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_0EC267DD362071635D005B4F0A4A0C73" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_A40FEED4146E31FB43225B4F0A4A365E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_A40FEED4146E31FB43225B4F0A4A365E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_3B63F74DF60E9BBFCF825B4F0A4ABECD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_3B63F74DF60E9BBFCF825B4F0A4ABECD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_24DDB3BF1B05AD9A9B695B4F0A4A0857" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_24DDB3BF1B05AD9A9B695B4F0A4A0857" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_13F624375DA3964439185B4F0A59DFE5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_SecuredLoansMember_13F624375DA3964439185B4F0A59DFE5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_9335922FD25A8A8BDCD15B4F0A59E4DE" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_UnsecuredLoansMember_9335922FD25A8A8BDCD15B4F0A59E4DE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_81CD9648ACF2279692B15B4F0A59649D" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_OneToFourFamilyResidentialMember_81CD9648ACF2279692B15B4F0A59649D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_0279F5F74FA69E80CC9C5B4F0A590E77" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_CommercialLandMember_0279F5F74FA69E80CC9C5B4F0A590E77" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_D506A461E60134C4FD305B4F0A59E9AB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_OwnerOccupiedMember_D506A461E60134C4FD305B4F0A59E9AB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_D7334B043536477916645B4F0A59404D" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_LandAndAcquisitionMember_D7334B043536477916645B4F0A59404D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_7FF7043AFCAE8472A4115B4F0A59373B" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_ResidentialConstructionMember_7FF7043AFCAE8472A4115B4F0A59373B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_81CA5C10528B46F91CFF5B4F0A59E28B" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_IncomePropertyMultifamilyMember_81CA5C10528B46F91CFF5B4F0A59E28B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_64DF8CE348252E62F5885B4F0A5921B0" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0BE96BAE546324356BBD5B4F0A4A523B" xlink:to="loc_colb_OwnerOccupiedConstructionMember_64DF8CE348252E62F5885B4F0A5921B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentCurrent" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_55822A7670D3CFBFCC2F5B4F0A598934" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_55822A7670D3CFBFCC2F5B4F0A598934" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDue" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_2629AD1EA1F1AE6F95305B4F0A59B059" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_2629AD1EA1F1AE6F95305B4F0A59B059" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_6485BFC35FC91A7A4C7E5B4F0A59608A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_6485BFC35FC91A7A4C7E5B4F0A59608A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableNet" xlink:label="loc_us-gaap_LoansReceivableNet_D05813BA2ACA55C72ED65B4F0A59443B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_4692EF6C70628E1658BB5B4F0A591788" xlink:to="loc_us-gaap_LoansReceivableNet_D05813BA2ACA55C72ED65B4F0A59443B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansAnalysisOfImpairedLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithoutRelatedAllowanceAxis" xlink:label="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceAxis_964569F09EB2C02A2F6C5B4F0AF55163" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:to="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceAxis_964569F09EB2C02A2F6C5B4F0AF55163" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain" xlink:label="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain_90EE7D467DE8BDB1B5065B4F0AF57418_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceAxis_964569F09EB2C02A2F6C5B4F0AF55163" xlink:to="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain_90EE7D467DE8BDB1B5065B4F0AF57418_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain" xlink:label="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain_90EE7D467DE8BDB1B5065B4F0AF57418" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceAxis_964569F09EB2C02A2F6C5B4F0AF55163" xlink:to="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain_90EE7D467DE8BDB1B5065B4F0AF57418" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansWithoutRecordedAllowanceMember" xlink:label="loc_colb_ImpairedLoansWithoutRecordedAllowanceMember_EC92CF608C13AE62EE535B4F0AF50982" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ImpairedFinancingReceivableWithoutRelatedAllowanceDomain_90EE7D467DE8BDB1B5065B4F0AF57418" xlink:to="loc_colb_ImpairedLoansWithoutRecordedAllowanceMember_EC92CF608C13AE62EE535B4F0AF50982" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithAllowanceAxis" xlink:label="loc_colb_ImpairedFinancingReceivableWithAllowanceAxis_986455ED29CC9A8593415B4F0AF5C1D4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:to="loc_colb_ImpairedFinancingReceivableWithAllowanceAxis_986455ED29CC9A8593415B4F0AF5C1D4" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithAllowanceDomain" xlink:label="loc_colb_ImpairedFinancingReceivableWithAllowanceDomain_4B7D08E28DE38E2E26485B4F0AF5BAF8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_ImpairedFinancingReceivableWithAllowanceAxis_986455ED29CC9A8593415B4F0AF5C1D4" xlink:to="loc_colb_ImpairedFinancingReceivableWithAllowanceDomain_4B7D08E28DE38E2E26485B4F0AF5BAF8_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedFinancingReceivableWithAllowanceDomain" xlink:label="loc_colb_ImpairedFinancingReceivableWithAllowanceDomain_4B7D08E28DE38E2E26485B4F0AF5BAF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_ImpairedFinancingReceivableWithAllowanceAxis_986455ED29CC9A8593415B4F0AF5C1D4" xlink:to="loc_colb_ImpairedFinancingReceivableWithAllowanceDomain_4B7D08E28DE38E2E26485B4F0AF5BAF8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_95E51542A0AA644ECDD25B4F0AF555F0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:to="loc_colb_LoansByMajorCategoryAxis_95E51542A0AA644ECDD25B4F0AF555F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_C1E8B1F09C5E7CB892A45B4F0AF59D03_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_95E51542A0AA644ECDD25B4F0AF555F0" xlink:to="loc_colb_LoansByMajorCategoryDomain_C1E8B1F09C5E7CB892A45B4F0AF59D03_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_C1E8B1F09C5E7CB892A45B4F0AF59D03" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_95E51542A0AA644ECDD25B4F0AF555F0" xlink:to="loc_colb_LoansByMajorCategoryDomain_C1E8B1F09C5E7CB892A45B4F0AF59D03" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_DABA0B980E10778C606E5B4F0AF564E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_C1E8B1F09C5E7CB892A45B4F0AF59D03" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_DABA0B980E10778C606E5B4F0AF564E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9A1BBE5677FDBEF2CAE75B4F0B05BEF5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_36DAC06AE043735D0F245B4F0AF56885" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9A1BBE5677FDBEF2CAE75B4F0B05BEF5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9A1BBE5677FDBEF2CAE75B4F0B05BEF5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9A1BBE5677FDBEF2CAE75B4F0B05BEF5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_E1365B48E1C3F9F471675B4F0B054893" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_E1365B48E1C3F9F471675B4F0B054893" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_9C7E301664003BB1A0A55B4F0B0575F0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_SecuredLoansMember_9C7E301664003BB1A0A55B4F0B0575F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_F9A8EF3BB77F0D4250BE5B4F0B05CA42" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_UnsecuredLoansMember_F9A8EF3BB77F0D4250BE5B4F0B05CA42" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_1E57521BA723CA891C575B4F0B052D30" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_OneToFourFamilyResidentialMember_1E57521BA723CA891C575B4F0B052D30" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_D08B9EC46A1775702BE85B4F0B058DB4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_CommercialLandMember_D08B9EC46A1775702BE85B4F0B058DB4" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_ACDB0604D0D7308140945B4F0B05B818" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_IncomePropertyMultifamilyMember_ACDB0604D0D7308140945B4F0B05B818" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_6AD1D0CF008855F8489D5B4F0B05D740" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_OwnerOccupiedMember_6AD1D0CF008855F8489D5B4F0B05D740" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_5D8BA46768411D9F99B55B4F0B050F48" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_LandAndAcquisitionMember_5D8BA46768411D9F99B55B4F0B050F48" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_E25CA47CD53899CB1DD05B4F0B05BC7E" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_ResidentialConstructionMember_E25CA47CD53899CB1DD05B4F0B05BC7E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_723704EE8220467F15825B4F0B05DC9E" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_723704EE8220467F15825B4F0B05DC9E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_B0602E61B59C719105035B4F0B05A9C7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_OwnerOccupiedConstructionMember_B0602E61B59C719105035B4F0B05A9C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_73A55C251098C5CC98405B4F0B056FB2" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_73A55C251098C5CC98405B4F0B056FB2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansWithoutRecordedAllowanceMember" xlink:label="loc_colb_ImpairedLoansWithoutRecordedAllowanceMember_23AAFC4CC05471B8EE655B4F0B0596A5" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_ImpairedLoansWithoutRecordedAllowanceMember_23AAFC4CC05471B8EE655B4F0B0596A5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ImpairedLoansWithRecordedAllowanceMember" xlink:label="loc_colb_ImpairedLoansWithRecordedAllowanceMember_6A525D76EA95174F1E545B4F0B0573D5" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4674AFB95E32C2C151525B4F0B052881" xlink:to="loc_colb_ImpairedLoansWithRecordedAllowanceMember_6A525D76EA95174F1E545B4F0B0573D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_48E4AF13C260DD191E805B4F0B05602E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_48E4AF13C260DD191E805B4F0B05602E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment" xlink:label="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_3E75A9EAEAE88318A34A5B4F0B0593BF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_3E75A9EAEAE88318A34A5B4F0B0593BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment" xlink:label="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_C49881B0BAEF188556965B4F0B052E77" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_C49881B0BAEF188556965B4F0B052E77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_D1CB5478F224E5FD71E45B4F0B052604" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_D1CB5478F224E5FD71E45B4F0B052604" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_71B20F7FC119838CD2855B4F0B0569E1" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_71B20F7FC119838CD2855B4F0B0569E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_BC5A524B420252F6CAE15B4F0B05EE9C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_BC5A524B420252F6CAE15B4F0B05EE9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment" xlink:label="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_BFD58F9092DAF82607915B4F0B05C863" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_BFD58F9092DAF82607915B4F0B05C863" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod" xlink:label="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_C1B7E436BB37930DAC885B4F0B051332" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_874FB785545CD656E3FD5B4F0B05085B" xlink:to="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_C1B7E436BB37930DAC885B4F0B051332" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansAnalysisOfLoanPortfolioByMajorTypesOfLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_153BE52527317A13EF875B4F076CA26A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_153BE52527317A13EF875B4F076CA26A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_B15FB8B4591F9D3603C75B4F076CF4D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_153BE52527317A13EF875B4F076CA26A" xlink:to="loc_colb_LoansByMajorCategoryAxis_B15FB8B4591F9D3603C75B4F076CF4D6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_B15FB8B4591F9D3603C75B4F076CF4D6" xlink:to="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_B15FB8B4591F9D3603C75B4F076CF4D6" xlink:to="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_F32AB6258A73C13698FD5B4F076C21C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_F32AB6258A73C13698FD5B4F076C21C6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_18F44D665F79F82037AB5B4F076C46A2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_51D008EDFE8BE2AE6FF95B4F076C9EE3" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_18F44D665F79F82037AB5B4F076C46A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_DFC1E411459E3447B8B75B4F076CDCAE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_153BE52527317A13EF875B4F076CA26A" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_DFC1E411459E3447B8B75B4F076CDCAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_DFC1E411459E3447B8B75B4F076CDCAE" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_DFC1E411459E3447B8B75B4F076CDCAE" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_2D86DBB3E97DCE3DC3FD5B4F076C940A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_colb_OneToFourFamilyResidentialMember_2D86DBB3E97DCE3DC3FD5B4F076C940A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialAndMultifamilyResidentialMember" xlink:label="loc_colb_CommercialAndMultifamilyResidentialMember_A3759665C834B8D011005B4F076C48F4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_colb_CommercialAndMultifamilyResidentialMember_A3759665C834B8D011005B4F076C48F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_37549DDFF5D93B9453E95B4F076C21EF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_37549DDFF5D93B9453E95B4F076C21EF" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_7C10EEF1368E427AC8F95B4F076C4638" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_7C10EEF1368E427AC8F95B4F076C4638" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_0104E2EA17266391CC8C5B4F076C242B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_0104E2EA17266391CC8C5B4F076C242B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_D2831FCE16D9910F7F685B4F076C60E9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4ABF11CEE3AFCC396AEA5B4F076C5629" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_D2831FCE16D9910F7F685B4F076C60E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableCommercialAndIndustrial" xlink:label="loc_us-gaap_LoansReceivableCommercialAndIndustrial_6D0DE1BE2964ECD15EF85B4F076CF150" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansReceivableCommercialAndIndustrial_6D0DE1BE2964ECD15EF85B4F076CF150" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableConsumerMortgage" xlink:label="loc_us-gaap_LoansAndLeasesReceivableConsumerMortgage_655929C8D9B99C6B63785B4F076CD802" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableConsumerMortgage_655929C8D9B99C6B63785B4F076CD802" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableCommercialMortgage" xlink:label="loc_us-gaap_LoansReceivableCommercialMortgage_FA6341B562B9A0C7B74B5B4F076C953B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansReceivableCommercialMortgage_FA6341B562B9A0C7B74B5B4F076C953B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansReceivableRealEstateMortgage" xlink:label="loc_colb_LoansReceivableRealEstateMortgage_5BCF0A6CFC18A635469B5B4F076C8A32" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_colb_LoansReceivableRealEstateMortgage_5BCF0A6CFC18A635469B5B4F076C8A32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableConsumerConstruction" xlink:label="loc_us-gaap_LoansAndLeasesReceivableConsumerConstruction_D643EE29A2A1A0CD92245B4F076CD560" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableConsumerConstruction_D643EE29A2A1A0CD92245B4F076CD560" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableCommercialConstruction" xlink:label="loc_us-gaap_LoansReceivableCommercialConstruction_D3DE114066894B24949E5B4F076C4832" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansReceivableCommercialConstruction_D3DE114066894B24949E5B4F076C4832" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansReceivableRealEstateConstruction" xlink:label="loc_colb_LoansReceivableRealEstateConstruction_C5154FED8CA7639816865B4F076C4E10" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_colb_LoansReceivableRealEstateConstruction_C5154FED8CA7639816865B4F076C4E10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableConsumerOther" xlink:label="loc_us-gaap_LoansAndLeasesReceivableConsumerOther_4B507C254F132C5658D85B4F077C4587" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableConsumerOther_4B507C254F132C5658D85B4F077C4587" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableDeferredIncome_059C8A39AE6B2333FFB35B4F077C4236" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableDeferredIncome_059C8A39AE6B2333FFB35B4F077C4236" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_950DE66AA8186C18AC1E5B4F077CF990" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_950DE66AA8186C18AC1E5B4F077CF990" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_20E38CF94FBBC439419A5B4F077C7130" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_20E38CF94FBBC439419A5B4F077C7130" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_19313025C46353F2E5615B4F077CFB5D" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_19313025C46353F2E5615B4F077CFB5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_56A8BECC2310E2802B9C5B4F077CFE46" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_AD39F4FCE99F19E06AD75B4F076CF1DE" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_56A8BECC2310E2802B9C5B4F077CFE46" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansAnalysisOfNonaccrualLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_CBBB4703955BAE447CE55B4F07CA6F45" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_199EC9CD4066A2A3E9805B4F07BA7EBB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_CBBB4703955BAE447CE55B4F07CA6F45" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_199EC9CD4066A2A3E9805B4F07BA7EBB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_718AC505D03EB50E0C075B4F07BA1F55" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_199EC9CD4066A2A3E9805B4F07BA7EBB" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_718AC505D03EB50E0C075B4F07BA1F55" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_718AC505D03EB50E0C075B4F07BA1F55" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_718AC505D03EB50E0C075B4F07BA1F55" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_BCA1CEBE0361DC9ADD005B4F07BAFC31" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_BCA1CEBE0361DC9ADD005B4F07BAFC31" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_FB3597E18278F5ACF9515B4F07BA6E19" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_FB3597E18278F5ACF9515B4F07BA6E19" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_C6445084BD040D0539665B4F07BA70E0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_C6445084BD040D0539665B4F07BA70E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_1EF59A341FF6743696355B4F07CA475F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_1EF59A341FF6743696355B4F07CA475F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_BC20DD5010A27D7B758A5B4F07CA9465" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_SecuredLoansMember_BC20DD5010A27D7B758A5B4F07CA9465" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_B3861D7ACED4D7197B255B4F07CA08AA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_UnsecuredLoansMember_B3861D7ACED4D7197B255B4F07CA08AA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_B338E55B8AC6D493D9F55B4F07CA62A8" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_OneToFourFamilyResidentialMember_B338E55B8AC6D493D9F55B4F07CA62A8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_152DD68BA6A4D324BC6B5B4F07CA6AAD" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_CommercialLandMember_152DD68BA6A4D324BC6B5B4F07CA6AAD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_0FC1F5B6F611E220353A5B4F07CABC95" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_IncomePropertyMultifamilyMember_0FC1F5B6F611E220353A5B4F07CABC95" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_6CC44639293452C7649B5B4F07CA9E31" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_OwnerOccupiedMember_6CC44639293452C7649B5B4F07CA9E31" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_97107769698CD590881E5B4F07CA0A95" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_LandAndAcquisitionMember_97107769698CD590881E5B4F07CA0A95" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_687FEA7081353CED34EF5B4F07CA9767" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_ResidentialConstructionMember_687FEA7081353CED34EF5B4F07CA9767" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_91CC27191E2A332B490C5B4F07CAD74A" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_91CC27191E2A332B490C5B4F07CAD74A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_B290BB527F4F7B0C919D5B4F07CA9295" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_38321714098F937C2A0E5B4F07BAB365" xlink:to="loc_colb_OwnerOccupiedConstructionMember_B290BB527F4F7B0C919D5B4F07CA9295" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_FE96B7B15945468354165B4F07CA0C41" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_CBBB4703955BAE447CE55B4F07CA6F45" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_FE96B7B15945468354165B4F07CA0C41" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableUnpaidPrincipalBalanceNonaccrualStatus" xlink:label="loc_colb_FinancingReceivableUnpaidPrincipalBalanceNonaccrualStatus_515497FEF450D52ABB9C5B4F07CA905C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_CBBB4703955BAE447CE55B4F07CA6F45" xlink:to="loc_colb_FinancingReceivableUnpaidPrincipalBalanceNonaccrualStatus_515497FEF450D52ABB9C5B4F07CA905C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableRecordedInvestmentGrossNonaccrualStatus" xlink:label="loc_colb_FinancingReceivableRecordedInvestmentGrossNonaccrualStatus_2B983C988A4C74C6E41D5B4F07CA9780" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_CBBB4703955BAE447CE55B4F07CA6F45" xlink:to="loc_colb_FinancingReceivableRecordedInvestmentGrossNonaccrualStatus_2B983C988A4C74C6E41D5B4F07CA9780" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansLoansAnalysisOfPurchasedCreditImpairedAccretableYieldRollforwardDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansLoansAnalysisOfPurchasedCreditImpairedLoansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_145673EC8E86838235A85B4F099E8C85" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_colb_LoansByMajorCategoryAxis_145673EC8E86838235A85B4F099E8C85" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_149E1936F1E494CCC8AA5B4F099E0FE2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_145673EC8E86838235A85B4F099E8C85" xlink:to="loc_colb_LoansByMajorCategoryDomain_149E1936F1E494CCC8AA5B4F099E0FE2_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_149E1936F1E494CCC8AA5B4F099E0FE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_145673EC8E86838235A85B4F099E8C85" xlink:to="loc_colb_LoansByMajorCategoryDomain_149E1936F1E494CCC8AA5B4F099E0FE2" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_A32732614B06C5C0BBC05B4F099E28D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_149E1936F1E494CCC8AA5B4F099E0FE2" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_A32732614B06C5C0BBC05B4F099E28D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis_3F8DA1A6AF0D168E43215B4F099E6F27" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis_3F8DA1A6AF0D168E43215B4F099E6F27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IndustryOfCounterpartyDomain" xlink:label="loc_us-gaap_IndustryOfCounterpartyDomain_D8703D4F58FD579D9EAA5B4F099E9478_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis_3F8DA1A6AF0D168E43215B4F099E6F27" xlink:to="loc_us-gaap_IndustryOfCounterpartyDomain_D8703D4F58FD579D9EAA5B4F099E9478_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IndustryOfCounterpartyDomain" xlink:label="loc_us-gaap_IndustryOfCounterpartyDomain_D8703D4F58FD579D9EAA5B4F099E9478" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis_3F8DA1A6AF0D168E43215B4F099E6F27" xlink:to="loc_us-gaap_IndustryOfCounterpartyDomain_D8703D4F58FD579D9EAA5B4F099E9478" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_2FD9018B766C1483FAF35B4F099E7E90" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_2FD9018B766C1483FAF35B4F099E7E90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_F8A2FB7B22F48C53DE115B4F099E4BE4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_2FD9018B766C1483FAF35B4F099E7E90" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_F8A2FB7B22F48C53DE115B4F099E4BE4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_F8A2FB7B22F48C53DE115B4F099E4BE4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_2FD9018B766C1483FAF35B4F099E7E90" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_F8A2FB7B22F48C53DE115B4F099E4BE4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="loc_srt_CounterpartyNameAxis_9EF0F349603E38A575655B4F099E8B24" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_srt_CounterpartyNameAxis_9EF0F349603E38A575655B4F099E8B24" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5A01CBE6C12EC53BF75A5B4F099EBE57_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_9EF0F349603E38A575655B4F099E8B24" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5A01CBE6C12EC53BF75A5B4F099EBE57_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5A01CBE6C12EC53BF75A5B4F099EBE57" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_9EF0F349603E38A575655B4F099E8B24" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5A01CBE6C12EC53BF75A5B4F099EBE57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_7578C6CEE5733D48E38A5B4F099E5268" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_srt_ProductOrServiceAxis_7578C6CEE5733D48E38A5B4F099E5268" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_4571D48A9132DFDF4F5B5B4F099EE1E6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_7578C6CEE5733D48E38A5B4F099E5268" xlink:to="loc_srt_ProductsAndServicesDomain_4571D48A9132DFDF4F5B5B4F099EE1E6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_4571D48A9132DFDF4F5B5B4F099EE1E6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_7578C6CEE5733D48E38A5B4F099E5268" xlink:to="loc_srt_ProductsAndServicesDomain_4571D48A9132DFDF4F5B5B4F099EE1E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidationItemsAxis" xlink:label="loc_srt_ConsolidationItemsAxis_0C7CEBBA9AE4745A58EF5B4F099EC293" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_srt_ConsolidationItemsAxis_0C7CEBBA9AE4745A58EF5B4F099EC293" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_354298F259D9D137304D5B4F099EC837_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_0C7CEBBA9AE4745A58EF5B4F099EC293" xlink:to="loc_srt_ConsolidationItemsDomain_354298F259D9D137304D5B4F099EC837_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_354298F259D9D137304D5B4F099EC837" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_0C7CEBBA9AE4745A58EF5B4F099EC293" xlink:to="loc_srt_ConsolidationItemsDomain_354298F259D9D137304D5B4F099EC837" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9F05D8654CDE014698885B4F099E785E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9F05D8654CDE014698885B4F099E785E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_53C78041B1E48FE273945B4F099E5C61_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9F05D8654CDE014698885B4F099E785E" xlink:to="loc_us-gaap_SegmentDomain_53C78041B1E48FE273945B4F099E5C61_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_53C78041B1E48FE273945B4F099E5C61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9F05D8654CDE014698885B4F099E785E" xlink:to="loc_us-gaap_SegmentDomain_53C78041B1E48FE273945B4F099E5C61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_678801B0A75937DDE46A5B4F099ECA8F" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_srt_StatementGeographicalAxis_678801B0A75937DDE46A5B4F099ECA8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_CAE73B80194FE8DF67B15B4F099E39B4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_678801B0A75937DDE46A5B4F099ECA8F" xlink:to="loc_srt_SegmentGeographicalDomain_CAE73B80194FE8DF67B15B4F099E39B4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_CAE73B80194FE8DF67B15B4F099E39B4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_678801B0A75937DDE46A5B4F099ECA8F" xlink:to="loc_srt_SegmentGeographicalDomain_CAE73B80194FE8DF67B15B4F099E39B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_9E8590D0A4704F905A995B4F099EF962" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_9E8590D0A4704F905A995B4F099EF962" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReceivablesBillingStatusDomain" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_861F7B9090C83148B4EB5B4F099EB5C9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_9E8590D0A4704F905A995B4F099EF962" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_861F7B9090C83148B4EB5B4F099EB5C9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReceivablesBillingStatusDomain" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_861F7B9090C83148B4EB5B4F099EB5C9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_9E8590D0A4704F905A995B4F099EF962" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_861F7B9090C83148B4EB5B4F099EB5C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_D16017949097950DB73E5B4F099EF7B9" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_D16017949097950DB73E5B4F099EF7B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="loc_us-gaap_ReceivableTypeDomain_D70785AC1A5E1E937A795B4F099E41BA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_D16017949097950DB73E5B4F099EF7B9" xlink:to="loc_us-gaap_ReceivableTypeDomain_D70785AC1A5E1E937A795B4F099E41BA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="loc_us-gaap_ReceivableTypeDomain_D70785AC1A5E1E937A795B4F099E41BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_D16017949097950DB73E5B4F099EF7B9" xlink:to="loc_us-gaap_ReceivableTypeDomain_D70785AC1A5E1E937A795B4F099E41BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_31E882D4DEC2C00501A15B4F099ECF86" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_31E882D4DEC2C00501A15B4F099ECF86" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_31E882D4DEC2C00501A15B4F099ECF86" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_31E882D4DEC2C00501A15B4F099ECF86" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_5EA9AB50794A6513C2F05B4F099EC181" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_5EA9AB50794A6513C2F05B4F099EC181" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_8CECE6A3E9AC1E052B615B4F099E3420" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_OneToFourFamilyResidentialMember_8CECE6A3E9AC1E052B615B4F099E3420" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialAndMultifamilyResidentialMember" xlink:label="loc_colb_CommercialAndMultifamilyResidentialMember_47E3FF363EFBBDAE827E5B4F099ED0DC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_CommercialAndMultifamilyResidentialMember_47E3FF363EFBBDAE827E5B4F099ED0DC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstatePortfolioSegmentMember" xlink:label="loc_colb_RealEstatePortfolioSegmentMember_51A6AE3C99652E9B0F605B4F099E37F0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_RealEstatePortfolioSegmentMember_51A6AE3C99652E9B0F605B4F099E37F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OnetoFourFamilyResidentialConstructionDomain" xlink:label="loc_colb_OnetoFourFamilyResidentialConstructionDomain_C165F4563F6F9300793B5B4F099EBCA5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_OnetoFourFamilyResidentialConstructionDomain_C165F4563F6F9300793B5B4F099EBCA5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialandMultifamilyResidentialConstructionDomain" xlink:label="loc_colb_CommercialandMultifamilyResidentialConstructionDomain_67075A35B131CD021CA65B4F099E4B9D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_CommercialandMultifamilyResidentialConstructionDomain_67075A35B131CD021CA65B4F099E4B9D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateConstructionPortfolioSegmentMember" xlink:label="loc_colb_RealEstateConstructionPortfolioSegmentMember_A583C05C1E3F7A0D1ED95B4F099EAB58" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_colb_RealEstateConstructionPortfolioSegmentMember_A583C05C1E3F7A0D1ED95B4F099EAB58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_A2B3ECA6A4E4FB986C8A5B4F099EB31E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5CEC2B16CB07023C13455B4F099EC9B9" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_A2B3ECA6A4E4FB986C8A5B4F099EB31E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8D675E760DA1A9181BB55B4F099E1ACB" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_EC56DBDABE71858D19B75B4F099E5B35" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8D675E760DA1A9181BB55B4F099E1ACB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5637BA12495F12D4AC185B4F099E1690_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8D675E760DA1A9181BB55B4F099E1ACB" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5637BA12495F12D4AC185B4F099E1690_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5637BA12495F12D4AC185B4F099E1690" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8D675E760DA1A9181BB55B4F099E1ACB" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5637BA12495F12D4AC185B4F099E1690" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableGrossCarryingAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_AF866765328DDAAC1A2A5B4F099EBC78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:to="loc_us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_AF866765328DDAAC1A2A5B4F099EBC78" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AcquisitionAccountingValuationDiscountOnCoveredLoans" xlink:label="loc_colb_AcquisitionAccountingValuationDiscountOnCoveredLoans_A98D818DF744647415115B4F09AED83A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:to="loc_colb_AcquisitionAccountingValuationDiscountOnCoveredLoans_A98D818DF744647415115B4F09AED83A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowance_47CD30B5B423154C2D145B4F09AEBA34" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowance_47CD30B5B423154C2D145B4F09AEBA34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_A189FFFC6D888F0E9B535B4F09AEBF4A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_ACA2B5FC9DB62DD7128C5B4F099E8E3D" xlink:to="loc_us-gaap_LoansAndLeasesReceivableNetReportedAmount_A189FFFC6D888F0E9B535B4F09AEBF4A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansLoansAnalysisOfTroubledDebtRestructuringsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_A3679655F7154BBF04C1A54E6D95C692" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_A3679655F7154BBF04C1A54E6D95C692" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_BAF287AAD66EA1910BEAA54E6D95862C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_A3679655F7154BBF04C1A54E6D95C692" xlink:to="loc_colb_LoansByMajorCategoryAxis_BAF287AAD66EA1910BEAA54E6D95862C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_073FF8472819F9C6D084A54E6D958D96_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_BAF287AAD66EA1910BEAA54E6D95862C" xlink:to="loc_colb_LoansByMajorCategoryDomain_073FF8472819F9C6D084A54E6D958D96_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_073FF8472819F9C6D084A54E6D958D96" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_BAF287AAD66EA1910BEAA54E6D95862C" xlink:to="loc_colb_LoansByMajorCategoryDomain_073FF8472819F9C6D084A54E6D958D96" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_B31EEF01E5A661DD57BBA54E6D95DBE3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_073FF8472819F9C6D084A54E6D958D96" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_B31EEF01E5A661DD57BBA54E6D95DBE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_F4E472F98D39A99A9501A54E6D952C1D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_A3679655F7154BBF04C1A54E6D95C692" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_F4E472F98D39A99A9501A54E6D952C1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_F4E472F98D39A99A9501A54E6D952C1D" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_F4E472F98D39A99A9501A54E6D952C1D" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuredLoansMember" xlink:label="loc_colb_SecuredLoansMember_44A3999597219538F7A7A54E6D95D97D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_SecuredLoansMember_44A3999597219538F7A7A54E6D95D97D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_UnsecuredLoansMember" xlink:label="loc_colb_UnsecuredLoansMember_33591419D9FADB73214AA54E6D95E15C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_UnsecuredLoansMember_33591419D9FADB73214AA54E6D95E15C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_CCF307737DEE38CBC17FA54E6D956399" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_OneToFourFamilyResidentialMember_CCF307737DEE38CBC17FA54E6D956399" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommercialLandMember" xlink:label="loc_colb_CommercialLandMember_F7FA6111CD45078DD512A54E6D95FFB9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_CommercialLandMember_F7FA6111CD45078DD512A54E6D95FFB9" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyMember" xlink:label="loc_colb_IncomePropertyMultifamilyMember_911045FEC299294D2E84A54E6D95B9F6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_IncomePropertyMultifamilyMember_911045FEC299294D2E84A54E6D95B9F6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedMember" xlink:label="loc_colb_OwnerOccupiedMember_DA8E1E18969F0B857907A54E6D957036" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_OwnerOccupiedMember_DA8E1E18969F0B857907A54E6D957036" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LandAndAcquisitionMember" xlink:label="loc_colb_LandAndAcquisitionMember_090FCBC46F66DAB2B5EEA54E6D956E83" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_LandAndAcquisitionMember_090FCBC46F66DAB2B5EEA54E6D956E83" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ResidentialConstructionMember" xlink:label="loc_colb_ResidentialConstructionMember_A8D9B816306DB3130BBBA54E6D95D608" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_ResidentialConstructionMember_A8D9B816306DB3130BBBA54E6D95D608" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomePropertyMultifamilyConstructionMember" xlink:label="loc_colb_IncomePropertyMultifamilyConstructionMember_319F6BBA897DD9D5B220A54E6D950EAC" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_IncomePropertyMultifamilyConstructionMember_319F6BBA897DD9D5B220A54E6D950EAC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OwnerOccupiedConstructionMember" xlink:label="loc_colb_OwnerOccupiedConstructionMember_C7AE51BFFEF1CE7ADA6BA54E6D95C781" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_colb_OwnerOccupiedConstructionMember_C7AE51BFFEF1CE7ADA6BA54E6D95C781" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_180FE234C09953DA311BA54E6D95F0E0" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_FD3616CDA584FA3CF90EA54E6D956C0C" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_180FE234C09953DA311BA54E6D95F0E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_3BDE78AD611997B12079A54E6D9560F8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_3BDE78AD611997B12079A54E6D9560F8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableModificationsAdditionalCommitmentToLend" xlink:label="loc_colb_FinancingReceivableModificationsAdditionalCommitmentToLend_2FE3F1DE07DC9DFAA4CBA54E6D951256" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_colb_FinancingReceivableModificationsAdditionalCommitmentToLend_2FE3F1DE07DC9DFAA4CBA54E6D951256" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_62B1916BDE44CFBBD067A54E6D95E73F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_62B1916BDE44CFBBD067A54E6D95E73F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_41D5A2818BCF0AF5613CA54E6D95AB50" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_41D5A2818BCF0AF5613CA54E6D95AB50" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2" xlink:label="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_B98EF9740A33B473B715A54E6D95CB7E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_B98EF9740A33B473B715A54E6D95CB7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_C93FC08981E72F15C80DA54E6D9573B1" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_C93FC08981E72F15C80DA54E6D9573B1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans" xlink:label="loc_colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans_67A64DC990913090C58BA54E6D95A4FC" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_9951963C611F5DCCB013A54E6D9557E0" xlink:to="loc_colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans_67A64DC990913090C58BA54E6D95A4FC" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_CEF7C63FBF65B2C185935CE390D2E372" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_CEF7C63FBF65B2C185935CE390D2E372" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_736C17FBEED4F1155F645CE390D2B44B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_CEF7C63FBF65B2C185935CE390D2E372" xlink:to="loc_us-gaap_FinancialInstrumentAxis_736C17FBEED4F1155F645CE390D2B44B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_736C17FBEED4F1155F645CE390D2B44B" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_736C17FBEED4F1155F645CE390D2B44B" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableMember" xlink:label="loc_us-gaap_LoansReceivableMember_9EFBD841531F436FCE235CE390D2D56D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272" xlink:to="loc_us-gaap_LoansReceivableMember_9EFBD841531F436FCE235CE390D2D56D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommercialLoanMember" xlink:label="loc_us-gaap_CommercialLoanMember_BC476976186549C1AAAB5CE390D2F7FE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2C024A01B6207E572EF15CE390D28272" xlink:to="loc_us-gaap_CommercialLoanMember_BC476976186549C1AAAB5CE390D2F7FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableRelatedParties" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_40D648585F8EA50DC8735CE390D28AD9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_40D648585F8EA50DC8735CE390D28AD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_74D460F0543EA183073A5CE390D24579" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_74D460F0543EA183073A5CE390D24579" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_688118611E8691DAD51A5CE390D2E65C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_688118611E8691DAD51A5CE390D2E65C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoanspledgedtocollateralizeFederalHomeLoanBankAdvances" xlink:label="loc_colb_LoanspledgedtocollateralizeFederalHomeLoanBankAdvances_1C15F2E70FF99BD80C4A5CE390D2717D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_colb_LoanspledgedtocollateralizeFederalHomeLoanBankAdvances_1C15F2E70FF99BD80C4A5CE390D2717D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoanspledgedtocollateralizeFederalReserveBankBorrowings" xlink:label="loc_colb_LoanspledgedtocollateralizeFederalReserveBankBorrowings_F10D672FBE2C291542885CE390D29F44" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_colb_LoanspledgedtocollateralizeFederalReserveBankBorrowings_F10D672FBE2C291542885CE390D29F44" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_8B340965537E7C7B324F5CE390D2F354" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_8B340965537E7C7B324F5CE390D2F354" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans" xlink:label="loc_us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans_73FA56A4E8A01F8759155CE390D23CB0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans_73FA56A4E8A01F8759155CE390D23CB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_B9FCF01CB3AD7BCFEF365CE390D2B0D4" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_B9FCF01CB3AD7BCFEF365CE390D2B0D4" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans" xlink:label="loc_colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans_57C40FE2EB31D2FA533F5CE390D2C17B" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_colb_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingNumberOfLoans_57C40FE2EB31D2FA533F5CE390D2C17B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansAndLeasesReceivableNonaccrualOfInterestCommitmentsOfAdditionalFunds" xlink:label="loc_colb_LoansAndLeasesReceivableNonaccrualOfInterestCommitmentsOfAdditionalFunds_C4CC507215371EBBAFAB5CE390D22320" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_colb_LoansAndLeasesReceivableNonaccrualOfInterestCommitmentsOfAdditionalFunds_C4CC507215371EBBAFAB5CE390D22320" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FinancingReceivableModificationsAdditionalCommitmentToLend" xlink:label="loc_colb_FinancingReceivableModificationsAdditionalCommitmentToLend_D9B9E700C5CCDE8F0DFB5CE390D2507C" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_colb_FinancingReceivableModificationsAdditionalCommitmentToLend_D9B9E700C5CCDE8F0DFB5CE390D2507C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_B6ACE9DF33B1AC23A3975CE390D24378" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_B223424CFF74F8B393F35CE390D295F2" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_B6ACE9DF33B1AC23A3975CE390D24378" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/LoansTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_89D44626FF08155D96FE5B4F0931C404" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_89D44626FF08155D96FE5B4F0931C404" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_8C5E008CD89A03116A265B4F0931D073" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_89D44626FF08155D96FE5B4F0931C404" xlink:to="loc_colb_LoansByMajorCategoryAxis_8C5E008CD89A03116A265B4F0931D073" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_8C5E008CD89A03116A265B4F0931D073" xlink:to="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_8C5E008CD89A03116A265B4F0931D073" xlink:to="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansExcludingPurchasedCreditImpairedLoansMember" xlink:label="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_1BF327BADBE6CB7F81A95B4F09319EBB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F" xlink:to="loc_colb_LoansExcludingPurchasedCreditImpairedLoansMember_1BF327BADBE6CB7F81A95B4F09319EBB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_5B017096DF3990C29ABB5B4F0931F20B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_921F853D59817F3BA0F45B4F0931B53F" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_5B017096DF3990C29ABB5B4F0931F20B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_370038178B80D06568E05B4F09313419" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_370038178B80D06568E05B4F09313419" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_5279E881B09823BD38A15B4F093126CA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_5279E881B09823BD38A15B4F093126CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PastDueFinancingReceivablesTableTextBlock" xlink:label="loc_us-gaap_PastDueFinancingReceivablesTableTextBlock_DF69228091A04EF0228F5B4F0931792F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_PastDueFinancingReceivablesTableTextBlock_DF69228091A04EF0228F5B4F0931792F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivablesTableTextBlock" xlink:label="loc_us-gaap_ImpairedFinancingReceivablesTableTextBlock_D0769EE849AE036554675B4F0931456A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_ImpairedFinancingReceivablesTableTextBlock_D0769EE849AE036554675B4F0931456A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock" xlink:label="loc_us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_DE32B3690590CF64339D5B4F0931D091" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_DE32B3690590CF64339D5B4F0931D091" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ChangesInAccretableYieldForAcquiredLoansTableTextBlock" xlink:label="loc_colb_ChangesInAccretableYieldForAcquiredLoansTableTextBlock_645DA3B318A41087BF155B4F093129CE" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_55175012A208D5EBF2525B4F0931FE3B" xlink:to="loc_colb_ChangesInAccretableYieldForAcquiredLoansTableTextBlock_645DA3B318A41087BF155B4F093129CE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/OtherRealEstateOwned" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/OtherRealEstateOwnedSummaryOfOtherRealEstateOwnedDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedLineItems" xlink:label="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedTable" xlink:label="loc_colb_OtherRealEstateOwnedTable_4FB1FBE4EF923E9D6F59B9E560DCE7F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_colb_OtherRealEstateOwnedTable_4FB1FBE4EF923E9D6F59B9E560DCE7F0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_2911A92CAD77287B0C87B9E560DCFB41" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_OtherRealEstateOwnedTable_4FB1FBE4EF923E9D6F59B9E560DCE7F0" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_2911A92CAD77287B0C87B9E560DCFB41" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D0FBB83CF032B77969A0B9E560EC27BF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_2911A92CAD77287B0C87B9E560DCFB41" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D0FBB83CF032B77969A0B9E560EC27BF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D0FBB83CF032B77969A0B9E560EC27BF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_2911A92CAD77287B0C87B9E560DCFB41" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D0FBB83CF032B77969A0B9E560EC27BF" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OneToFourFamilyResidentialMember" xlink:label="loc_colb_OneToFourFamilyResidentialMember_5EB90E63B00F718600E4B9E560ECC08D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_D0FBB83CF032B77969A0B9E560EC27BF" xlink:to="loc_colb_OneToFourFamilyResidentialMember_5EB90E63B00F718600E4B9E560ECC08D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateOwnedByTypeAxis" xlink:label="loc_colb_RealEstateOwnedByTypeAxis_F8A26C8B5900C4E8F405B9E560EC1B4D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_OtherRealEstateOwnedTable_4FB1FBE4EF923E9D6F59B9E560DCE7F0" xlink:to="loc_colb_RealEstateOwnedByTypeAxis_F8A26C8B5900C4E8F405B9E560EC1B4D" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateOwnedTypeDomain" xlink:label="loc_colb_RealEstateOwnedTypeDomain_36CC25E48713C70DD6BEB9E560EC64AD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_RealEstateOwnedByTypeAxis_F8A26C8B5900C4E8F405B9E560EC1B4D" xlink:to="loc_colb_RealEstateOwnedTypeDomain_36CC25E48713C70DD6BEB9E560EC64AD_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateOwnedTypeDomain" xlink:label="loc_colb_RealEstateOwnedTypeDomain_36CC25E48713C70DD6BEB9E560EC64AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_RealEstateOwnedByTypeAxis_F8A26C8B5900C4E8F405B9E560EC1B4D" xlink:to="loc_colb_RealEstateOwnedTypeDomain_36CC25E48713C70DD6BEB9E560EC64AD" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherRealEstateOwnedestablishedthroughacquisition" xlink:label="loc_colb_OtherRealEstateOwnedestablishedthroughacquisition_80AC28D0B7A7FFCC764DB9E560ECCDAE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_colb_OtherRealEstateOwnedestablishedthroughacquisition_80AC28D0B7A7FFCC764DB9E560ECCDAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateAcquiredThroughForeclosure" xlink:label="loc_us-gaap_RealEstateAcquiredThroughForeclosure_1D348DDF1BD34FB4F956B9E560EC763B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_us-gaap_RealEstateAcquiredThroughForeclosure_1D348DDF1BD34FB4F956B9E560EC763B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RealEstateAcquiredThroughForeclosureTransfersInNetOfWriteDowns" xlink:label="loc_colb_RealEstateAcquiredThroughForeclosureTransfersInNetOfWriteDowns_009C8C1B3D5D7C8E2854B9E560EC286E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_colb_RealEstateAcquiredThroughForeclosureTransfersInNetOfWriteDowns_009C8C1B3D5D7C8E2854B9E560EC286E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TransferOtherRealEstateWriteDown" xlink:label="loc_colb_TransferOtherRealEstateWriteDown_3D081CDF0CFB3D9C7954B9E560ECDEFC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_colb_TransferOtherRealEstateWriteDown_3D081CDF0CFB3D9C7954B9E560ECDEFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans" xlink:label="loc_us-gaap_ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans_3DB10DB580591E5C5B31B9E560EC7097" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_us-gaap_ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans_3DB10DB580591E5C5B31B9E560EC7097" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:label="loc_us-gaap_GainsLossesOnSalesOfOtherRealEstate_B0C987FA2DB0A15646DFB9E560ECAD52" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_us-gaap_GainsLossesOnSalesOfOtherRealEstate_B0C987FA2DB0A15646DFB9E560ECAD52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageLoansInProcessOfForeclosureAmount" xlink:label="loc_us-gaap_MortgageLoansInProcessOfForeclosureAmount_1348BF887F45759AF980B9E560ECF9CF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_OtherRealEstateOwnedLineItems_C6B01E5BB6075724BD63B9E560ECDA69" xlink:to="loc_us-gaap_MortgageLoansInProcessOfForeclosureAmount_1348BF887F45759AF980B9E560ECF9CF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/OtherRealEstateOwnedTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ParentCompanyFinancialInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E9D96528E8CC43FF31D75B4F08D32379" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E9D96528E8CC43FF31D75B4F08D32379" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E1F0EE68A2AA7B845C205B4F08D3B34A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E9D96528E8CC43FF31D75B4F08D32379" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E1F0EE68A2AA7B845C205B4F08D3B34A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E1F0EE68A2AA7B845C205B4F08D3B34A" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E1F0EE68A2AA7B845C205B4F08D3B34A" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BankingSubsidiariesMember" xlink:label="loc_colb_BankingSubsidiariesMember_1423EB9DC2B9A7F83F5A5B4F08D3D30E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677" xlink:to="loc_colb_BankingSubsidiariesMember_1423EB9DC2B9A7F83F5A5B4F08D3D30E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSubsidiariesMember" xlink:label="loc_colb_OtherSubsidiariesMember_9A3F9BA83F6F4A0B8A095B4F08D37BD8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_9C9564618839BB1A9CF65B4F08D36677" xlink:to="loc_colb_OtherSubsidiariesMember_9A3F9BA83F6F4A0B8A095B4F08D37BD8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="loc_srt_ConsolidatedEntitiesAxis_74CC165B4175D637D4365B4F08D3EE39" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E9D96528E8CC43FF31D75B4F08D32379" xlink:to="loc_srt_ConsolidatedEntitiesAxis_74CC165B4175D637D4365B4F08D3EE39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_15FD434795EE619921745B4F08D33F30_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_74CC165B4175D637D4365B4F08D3EE39" xlink:to="loc_srt_ConsolidatedEntitiesDomain_15FD434795EE619921745B4F08D33F30_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_15FD434795EE619921745B4F08D33F30" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_74CC165B4175D637D4365B4F08D3EE39" xlink:to="loc_srt_ConsolidatedEntitiesDomain_15FD434795EE619921745B4F08D33F30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ParentCompanyMember" xlink:label="loc_srt_ParentCompanyMember_774724B5DAC789A560F15B4F08D3186B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_15FD434795EE619921745B4F08D33F30" xlink:to="loc_srt_ParentCompanyMember_774724B5DAC789A560F15B4F08D3186B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:to="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndDueFromBanks" xlink:label="loc_us-gaap_CashAndDueFromBanks_6A1F7D10D08DF56FD78C5B4F08D3630C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_CashAndDueFromBanks_6A1F7D10D08DF56FD78C5B4F08D3630C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="loc_us-gaap_InterestBearingDepositsInBanks_89E9AEB96C0A6B76D6B95B4F08D3C040" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_InterestBearingDepositsInBanks_89E9AEB96C0A6B76D6B95B4F08D3C040" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_80F5E3BC0432B37906635B4F08D384F1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_80F5E3BC0432B37906635B4F08D384F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_0D99BB39A2704F9DBBF25B4F08D35061" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_EquityMethodInvestments_0D99BB39A2704F9DBBF25B4F08D35061" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_B7BEB96F4309403061045B4F08D3D5D3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_Goodwill_B7BEB96F4309403061045B4F08D3D5D3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_F181656DD49A2F4690E05B4F08D3F891" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_OtherAssets_F181656DD49A2F4690E05B4F08D3F891" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_3809C4B480ECF47A028E5B4F08D3A460" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_F2ACB91174085894A9C85B4F08D3DA3E" xlink:to="loc_us-gaap_Assets_3809C4B480ECF47A028E5B4F08D3A460" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedDebt" xlink:label="loc_us-gaap_SubordinatedDebt_BA5648C36460120A86525B4F08D31558" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:to="loc_us-gaap_SubordinatedDebt_BA5648C36460120A86525B4F08D31558" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_JuniorSubordinatedNotes" xlink:label="loc_us-gaap_JuniorSubordinatedNotes_50282A746FEEF03E0E855B4F08D3E57E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:to="loc_us-gaap_JuniorSubordinatedNotes_50282A746FEEF03E0E855B4F08D3E57E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2F53596C9E5B204F78DA5B4F08D3F948" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="loc_us-gaap_OtherLiabilities_7CDCED4ADE8B88138E745B4F08D3E39C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:to="loc_us-gaap_OtherLiabilities_7CDCED4ADE8B88138E745B4F08D3E39C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_6DDB0365E55A2D6794295B4F08D3FFB5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:to="loc_us-gaap_Liabilities_6DDB0365E55A2D6794295B4F08D3FFB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_79D24F8650CABE0AEF295B4F08D3FA79" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:to="loc_us-gaap_StockholdersEquity_79D24F8650CABE0AEF295B4F08D3FA79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_759036B15CA5B9C322C05B4F08D3289B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D2970ABA945B9628AADA5B4F08D361B9" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_759036B15CA5B9C322C05B4F08D3289B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedStatementsOfCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_3F9287DEB0AFFE3AD3705B4F08C41B04" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_2FAAD40EE2BFE072B51F5B4F08C474A9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_3F9287DEB0AFFE3AD3705B4F08C41B04" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_2FAAD40EE2BFE072B51F5B4F08C474A9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_E7993C51F30B32CAB36F5B4F08C47BD8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_2FAAD40EE2BFE072B51F5B4F08C474A9" xlink:to="loc_dei_LegalEntityAxis_E7993C51F30B32CAB36F5B4F08C47BD8" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_0B788C8094886FA001405B4F08C43496_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_E7993C51F30B32CAB36F5B4F08C47BD8" xlink:to="loc_dei_EntityDomain_0B788C8094886FA001405B4F08C43496_default" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_0B788C8094886FA001405B4F08C43496" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_E7993C51F30B32CAB36F5B4F08C47BD8" xlink:to="loc_dei_EntityDomain_0B788C8094886FA001405B4F08C43496" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="loc_srt_ConsolidatedEntitiesAxis_57003A0B3B6D4017221E5B4F08C495A6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_2FAAD40EE2BFE072B51F5B4F08C474A9" xlink:to="loc_srt_ConsolidatedEntitiesAxis_57003A0B3B6D4017221E5B4F08C495A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_A68AC55B5C8FA94F1F775B4F08C45DDB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_57003A0B3B6D4017221E5B4F08C495A6" xlink:to="loc_srt_ConsolidatedEntitiesDomain_A68AC55B5C8FA94F1F775B4F08C45DDB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_A68AC55B5C8FA94F1F775B4F08C45DDB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_57003A0B3B6D4017221E5B4F08C495A6" xlink:to="loc_srt_ConsolidatedEntitiesDomain_A68AC55B5C8FA94F1F775B4F08C45DDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ParentCompanyMember" xlink:label="loc_srt_ParentCompanyMember_E75AEEE2BF82C1A81D195B4F08C4844D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_A68AC55B5C8FA94F1F775B4F08C45DDB" xlink:to="loc_srt_ParentCompanyMember_E75AEEE2BF82C1A81D195B4F08C4844D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssued1" xlink:label="loc_us-gaap_StockIssued1_30B1EC10886A7899EF3C5B4F08C457FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_3F9287DEB0AFFE3AD3705B4F08C41B04" xlink:to="loc_us-gaap_StockIssued1_30B1EC10886A7899EF3C5B4F08C457FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_3F9287DEB0AFFE3AD3705B4F08C41B04" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_4BE49FA68875C17EEF025B4F08C483B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_4BE49FA68875C17EEF025B4F08C483B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_15024A4D8C5D6B152BFB5B4F08C4E1BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_4BE49FA68875C17EEF025B4F08C483B8" xlink:to="loc_us-gaap_NetIncomeLoss_15024A4D8C5D6B152BFB5B4F08C4E1BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_F852D8679B4B683E9F8E5B4F08C49559" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_4BE49FA68875C17EEF025B4F08C483B8" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_F852D8679B4B683E9F8E5B4F08C49559" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3EB93918D5CDD529DCC05B4F08C4ECC0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_F852D8679B4B683E9F8E5B4F08C49559" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_3EB93918D5CDD529DCC05B4F08C4ECC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_69965717F626EC46C6AF5B4F08C49EA6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_F852D8679B4B683E9F8E5B4F08C49559" xlink:to="loc_us-gaap_ShareBasedCompensation_69965717F626EC46C6AF5B4F08C49EA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_FEFCA7C9052F0A1F59425B4F08C4E64D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_F852D8679B4B683E9F8E5B4F08C49559" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_FEFCA7C9052F0A1F59425B4F08C4E64D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_20F84C6D7087BE03980C5B4F08C4A631" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_4BE49FA68875C17EEF025B4F08C483B8" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_20F84C6D7087BE03980C5B4F08C4A631" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAcquiredFromAcquisition" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_98E0EBA98E2A9980DCDD5B4F08C425E3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:to="loc_us-gaap_CashAcquiredFromAcquisition_98E0EBA98E2A9980DCDD5B4F08C425E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4E316EA16CE71F10B7025B4F08C4EF58" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4E316EA16CE71F10B7025B4F08C4EF58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_3ED7E212F4821E288C515B4F08C4240E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_4E316EA16CE71F10B7025B4F08C4EF58" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_3ED7E212F4821E288C515B4F08C4240E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xlink:label="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_7A1D8F14957DE82DE06C5B4F08C48853" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_7A1D8F14957DE82DE06C5B4F08C48853" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_A5200102E3EC393AD8225B4F08C4FBE2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_A5200102E3EC393AD8225B4F08C4FBE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfSubordinatedDebt" xlink:label="loc_us-gaap_RepaymentsOfSubordinatedDebt_0633CA1F0B1D7B569A5C5B4F08C45AA3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_RepaymentsOfSubordinatedDebt_0633CA1F0B1D7B569A5C5B4F08C45AA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfEquity_9673105E02D8D357D12E5B4F08C4F642" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfEquity_9673105E02D8D357D12E5B4F08C4F642" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_824AC65E6FA0D34AE5B05B4F08C464E0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_824AC65E6FA0D34AE5B05B4F08C464E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_AF57C1158C01C4EDA78C5B4F08C4E1EE" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_AF57C1158C01C4EDA78C5B4F08C4E1EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_1C7AA38AA07BC5EC535D5B4F08C4A335" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_1C7AA38AA07BC5EC535D5B4F08C4A335" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9C64A613415D1F6650075B4F08C4D466" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_A3AFF0A182DB65DF5D335B4F08C4BBB5" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_9C64A613415D1F6650075B4F08C4D466" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_223E2A62876AC6D2CE675B4F08C4DC26" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseAbstract_C97494587A553C373D4D5B4F08C49788" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_223E2A62876AC6D2CE675B4F08C4DC26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E5C12B0D0F9195EE06B45B4F08C4CC84" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_3F9287DEB0AFFE3AD3705B4F08C41B04" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E5C12B0D0F9195EE06B45B4F08C4CC84" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ParentCompanyFinancialInformationCondensedStatementsOfIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E80CA7BC1E79A36060977646DCD4DA75" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E80CA7BC1E79A36060977646DCD4DA75" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="loc_srt_ConsolidatedEntitiesAxis_E40E7F919430A70BE03B7646DCD528CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_E80CA7BC1E79A36060977646DCD4DA75" xlink:to="loc_srt_ConsolidatedEntitiesAxis_E40E7F919430A70BE03B7646DCD528CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_EAAC73008AE1CB24ECED7646DCD578B6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_E40E7F919430A70BE03B7646DCD528CF" xlink:to="loc_srt_ConsolidatedEntitiesDomain_EAAC73008AE1CB24ECED7646DCD578B6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain_EAAC73008AE1CB24ECED7646DCD578B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_E40E7F919430A70BE03B7646DCD528CF" xlink:to="loc_srt_ConsolidatedEntitiesDomain_EAAC73008AE1CB24ECED7646DCD578B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ParentCompanyMember" xlink:label="loc_srt_ParentCompanyMember_38E93288E5C6C4BD210C7646DCD5FB46" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_EAAC73008AE1CB24ECED7646DCD578B6" xlink:to="loc_srt_ParentCompanyMember_38E93288E5C6C4BD210C7646DCD5FB46" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomeAbstract" xlink:label="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentIncomeDividend" xlink:label="loc_us-gaap_InvestmentIncomeDividend_6CEBF75E3AC9FE64D3C77646DCF5DD4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:to="loc_us-gaap_InvestmentIncomeDividend_6CEBF75E3AC9FE64D3C77646DCF5DD4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_1D8AAA6B48E03438DF2D7646DCF51B72" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_1D8AAA6B48E03438DF2D7646DCF51B72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome" xlink:label="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_E66C62B58C4F993C993C7646DCF500E7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:to="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_E66C62B58C4F993C993C7646DCF500E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_9150681EFF9AEF9D0C627646DCF50BFA" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_IncomeAbstract_D96F76ED259EFFDDC5D47646DCD6F1EC" xlink:to="loc_us-gaap_Revenues_9150681EFF9AEF9D0C627646DCF50BFA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ExpenseAbstract" xlink:label="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="loc_us-gaap_LaborAndRelatedExpense_3427BCECC5D7E6D50A067646DCF5E516" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:to="loc_us-gaap_LaborAndRelatedExpense_3427BCECC5D7E6D50A067646DCF5E516" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_CC23F524FB79148E2C897646DCF52F9C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_CC23F524FB79148E2C897646DCF52F9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseOtherShortTermBorrowings" xlink:label="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_F1B3852FB29CBF06B5187646DCF5A417" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:to="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_F1B3852FB29CBF06B5187646DCF5A417" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="loc_us-gaap_OtherNoninterestExpense_05EFB8D0188B7F02AE2F7646DCF50EAB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:to="loc_us-gaap_OtherNoninterestExpense_05EFB8D0188B7F02AE2F7646DCF50EAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingCostsAndExpenses" xlink:label="loc_us-gaap_OperatingCostsAndExpenses_41D7E8C9DB3A1F39822F7646DCF58F1A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ExpenseAbstract_9A7326182A77D12CE5CB7646DCF564CC" xlink:to="loc_us-gaap_OperatingCostsAndExpenses_41D7E8C9DB3A1F39822F7646DCF58F1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6A2FDE0F7F500A7FAD9E7646DCF5D7FA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6A2FDE0F7F500A7FAD9E7646DCF5D7FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_06B6C2F48E63B558C8B27646DCF5473A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_06B6C2F48E63B558C8B27646DCF5473A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IncomeLossBeforeEquityInUndistributedNetIncomeLossOfSubsidiaries" xlink:label="loc_colb_IncomeLossBeforeEquityInUndistributedNetIncomeLossOfSubsidiaries_5253DD3DEC08BCF4C6627646DCF5846C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_colb_IncomeLossBeforeEquityInUndistributedNetIncomeLossOfSubsidiaries_5253DD3DEC08BCF4C6627646DCF5846C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions_806827A3281FECA228457646DCF5A94E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions_806827A3281FECA228457646DCF5A94E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_5B4561028CF67DA213867646DCF5668F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_57AC5B71F22758919D647646DCD60C85" xlink:to="loc_us-gaap_NetIncomeLoss_5B4561028CF67DA213867646DCF5668F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ParentCompanyFinancialInformationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/PremisesAndEquipment" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/PremisesAndEquipmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_60CC0553691D2F7FD5DE5B4F093118D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_60CC0553691D2F7FD5DE5B4F093118D9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71E383F5AD9FD63E2EB35B4F09310DA3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_60CC0553691D2F7FD5DE5B4F093118D9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71E383F5AD9FD63E2EB35B4F09310DA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71E383F5AD9FD63E2EB35B4F09310DA3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71E383F5AD9FD63E2EB35B4F09310DA3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LandMember" xlink:label="loc_us-gaap_LandMember_D444BABAB36E1538C04E5B4F09319041" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_LandMember_D444BABAB36E1538C04E5B4F09319041" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingMember" xlink:label="loc_us-gaap_BuildingMember_B04D1F33157E590651DD5B4F093105BA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_BuildingMember_B04D1F33157E590651DD5B4F093105BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_AD51B56AB2F1351C84535B4F09313704" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_AD51B56AB2F1351C84535B4F09313704" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_9C9F9A01C9CECF54916F5B4F0931A486" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_9C9F9A01C9CECF54916F5B4F0931A486" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VehiclesMember" xlink:label="loc_us-gaap_VehiclesMember_F7CCDC81C15808ABBB585B4F09312190" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_VehiclesMember_F7CCDC81C15808ABBB585B4F09312190" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_864178D4EF1106E2AD355B4F093151B8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7B6DB8336B5AC68341465B4F093115C5" xlink:to="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_864178D4EF1106E2AD355B4F093151B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_EA6B477BC7D766C58A055B4F0931244E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_EA6B477BC7D766C58A055B4F0931244E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_13EFC75AE112291967EE5B4F0931483E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_13EFC75AE112291967EE5B4F0931483E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_A917EE53A270D8F3216A5B4F093132DA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_A917EE53A270D8F3216A5B4F093132DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaap_DepreciationAndAmortization_CC1CBFADD1102283E17A5B4F09311019" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A67EE819F7DE56C950955B4F09312D4C" xlink:to="loc_us-gaap_DepreciationAndAmortization_CC1CBFADD1102283E17A5B4F09311019" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/PremisesAndEquipmentTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RegulatoryCapitalRequirements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RegulatoryCapitalRequirementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems" xlink:label="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable" xlink:label="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_66C17F2E3D0FE5FB51D35B4F0AB769FF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_66C17F2E3D0FE5FB51D35B4F0AB769FF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_A71507D6A56A769939E25B4F0AC68542" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_66C17F2E3D0FE5FB51D35B4F0AB769FF" xlink:to="loc_dei_LegalEntityAxis_A71507D6A56A769939E25B4F0AC68542" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8C81F00107E05E05FBC25B4F0AC699BA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_A71507D6A56A769939E25B4F0AC68542" xlink:to="loc_dei_EntityDomain_8C81F00107E05E05FBC25B4F0AC699BA_default" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8C81F00107E05E05FBC25B4F0AC699BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_A71507D6A56A769939E25B4F0AC68542" xlink:to="loc_dei_EntityDomain_8C81F00107E05E05FBC25B4F0AC699BA" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_BankingSubsidiariesMember" xlink:label="loc_colb_BankingSubsidiariesMember_0962C20B5BF3564AAD1A5B4F0AC62E6A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_8C81F00107E05E05FBC25B4F0AC699BA" xlink:to="loc_colb_BankingSubsidiariesMember_0962C20B5BF3564AAD1A5B4F0AC62E6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonEquityTierOneCapital" xlink:label="loc_us-gaap_CommonEquityTierOneCapital_AA60B927B2B3E4C4FD4B5B4F0AC62BF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CommonEquityTierOneCapital_AA60B927B2B3E4C4FD4B5B4F0AC62BF8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CapitalConservationBuffer" xlink:label="loc_colb_CapitalConservationBuffer_65679C7BCEA1328292565B4F0AC6EEFE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CapitalConservationBuffer_65679C7BCEA1328292565B4F0AC6EEFE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTier1CapitaltoRiskWeightedAssets" xlink:label="loc_colb_CommonEquityTier1CapitaltoRiskWeightedAssets_41C48B7BDBBDF441ADC05B4F0AC6139E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTier1CapitaltoRiskWeightedAssets_41C48B7BDBBDF441ADC05B4F0AC6139E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy" xlink:label="loc_us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy_CC757F700041219BE8D15B4F0AC6DFFB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy_CC757F700041219BE8D15B4F0AC6DFFB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssets" xlink:label="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssets_BDB9E7FC72C98879D88C5B4F0AC6D8D6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssets_BDB9E7FC72C98879D88C5B4F0AC6D8D6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein" xlink:label="loc_colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_875BCA60C009F941EA695B4F0AC6F641" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_875BCA60C009F941EA695B4F0AC6F641" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein" xlink:label="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_55EE52FB511F9BF301FC5B4F0AC6BD6F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_55EE52FB511F9BF301FC5B4F0AC6BD6F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacyminimumrequiredplusfullyphasedincapitalconservationbuffer" xlink:label="loc_colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacyminimumrequiredplusfullyphasedincapitalconservationbuffer_E73B91537A264A57A4545B4F0AC6DA44" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTierOneCapitalRequiredforCapitalAdequacyminimumrequiredplusfullyphasedincapitalconservationbuffer_E73B91537A264A57A4545B4F0AC6DA44" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin" xlink:label="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_8B062BA239A103FEC2215B4F0AC6899A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_8B062BA239A103FEC2215B4F0AC6899A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTierOneRiskBasedCapitalRequiredtobeWellCapitalized" xlink:label="loc_colb_CommonEquityTierOneRiskBasedCapitalRequiredtobeWellCapitalized_FC63D1C3909C865D37C45B4F0AC616CC" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTierOneRiskBasedCapitalRequiredtobeWellCapitalized_FC63D1C3909C865D37C45B4F0AC616CC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonEquityTier1RiskBasedCapitalRequiredtobeWellCapitalizedtoRiskWeightedAssets" xlink:label="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredtobeWellCapitalizedtoRiskWeightedAssets_7153C906A78F7AE744C85B4F0AC674F9" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CommonEquityTier1RiskBasedCapitalRequiredtobeWellCapitalizedtoRiskWeightedAssets_7153C906A78F7AE744C85B4F0AC674F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Capital" xlink:label="loc_us-gaap_Capital_51A5B593E6EA15B82B6F5B4F0AC600D4" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_Capital_51A5B593E6EA15B82B6F5B4F0AC600D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalToRiskWeightedAssets" xlink:label="loc_us-gaap_CapitalToRiskWeightedAssets_1CC23E516BCEFB3CDE785B4F0AC60AA0" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CapitalToRiskWeightedAssets_1CC23E516BCEFB3CDE785B4F0AC60AA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacy" xlink:label="loc_us-gaap_CapitalRequiredForCapitalAdequacy_76BA0D55A99F230776765B4F0AC6F9DB" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CapitalRequiredForCapitalAdequacy_76BA0D55A99F230776765B4F0AC6F9DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:label="loc_us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_CCAF9CA7E8AF0FCFE82E5B4F0AC6DE4B" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_CCAF9CA7E8AF0FCFE82E5B4F0AC6DE4B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein" xlink:label="loc_colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_4AA5AFE4D896F005DE605B4F0AC6BAC0" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_4AA5AFE4D896F005DE605B4F0AC6BAC0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein" xlink:label="loc_colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_74CA1919FE31CE9DFC9C5B4F0AC6ED86" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_74CA1919FE31CE9DFC9C5B4F0AC6ED86" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin" xlink:label="loc_colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin_ACC9FBE07DD7371990805B4F0AC69A46" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin_ACC9FBE07DD7371990805B4F0AC69A46" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin" xlink:label="loc_colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_1CA7988EC1B7EA0D9C325B4F0AC6CC7C" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_CapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_1CA7988EC1B7EA0D9C325B4F0AC6CC7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalized" xlink:label="loc_us-gaap_CapitalRequiredToBeWellCapitalized_E9D4CCA3C8009336AF5E5B4F0AC67B5B" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CapitalRequiredToBeWellCapitalized_E9D4CCA3C8009336AF5E5B4F0AC67B5B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:label="loc_us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_5DF1EBBB54A9E3E941575B4F0AC6B386" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_5DF1EBBB54A9E3E941575B4F0AC6B386" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapital" xlink:label="loc_us-gaap_TierOneRiskBasedCapital_8EA15A1FBC2CB910E1C95B4F0AC64254" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapital_8EA15A1FBC2CB910E1C95B4F0AC64254" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_5BC6616D09894729443D5B4F0AC6540B" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_5BC6616D09894729443D5B4F0AC6540B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_86F12137F16EA9E0EE0B5B4F0AC64864" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_86F12137F16EA9E0EE0B5B4F0AC64864" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_8488F492BC1A7FF58F365B4F0AC61846" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_8488F492BC1A7FF58F365B4F0AC61846" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein" xlink:label="loc_colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_13AF42466280231890CB5B4F0AC67E97" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferphasein_13AF42466280231890CB5B4F0AC67E97" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein" xlink:label="loc_colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_49425642B0D368ABE9A35B4F0AC62530" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferphasein_49425642B0D368ABE9A35B4F0AC62530" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin" xlink:label="loc_colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin_8ABBA53B5DA60A6B69485B4F0AC600E6" xlink:type="locator" />
    <link:definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_TierOneRiskBasedCapitalRequiredforCapitalAdequacypluscapitalconservationbufferfullyphasedin_8ABBA53B5DA60A6B69485B4F0AC600E6" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin" xlink:label="loc_colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_BB817BC5C2BB4FC5B8A45B4F0AC6C519" xlink:type="locator" />
    <link:definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_colb_TierOneBasedCapitalRequiredforCapitalAdequacytoRiskWeightedAssetspluscapitalconservationbufferfullyphasedin_BB817BC5C2BB4FC5B8A45B4F0AC6C519" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_D028D0A699A6414809B15B4F0AC64E71" xlink:type="locator" />
    <link:definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_D028D0A699A6414809B15B4F0AC64E71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_E835B9D57B0D10E679D15B4F0AC66904" xlink:type="locator" />
    <link:definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_E835B9D57B0D10E679D15B4F0AC66904" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapital" xlink:label="loc_us-gaap_TierOneLeverageCapital_054FDF9B4CA63AA55F125B4F0AC67150" xlink:type="locator" />
    <link:definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapital_054FDF9B4CA63AA55F125B4F0AC67150" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalToAverageAssets" xlink:label="loc_us-gaap_TierOneLeverageCapitalToAverageAssets_D8D1B7C2C0F4B588E1F35B4F0AC6D381" xlink:type="locator" />
    <link:definitionArc order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapitalToAverageAssets_D8D1B7C2C0F4B588E1F35B4F0AC6D381" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_4849EB3B02CFF882CA6B5B4F0AC6E46D" xlink:type="locator" />
    <link:definitionArc order="34" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_4849EB3B02CFF882CA6B5B4F0AC6E46D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_7730440095C4F9BA5AE55B4F0AC6D991" xlink:type="locator" />
    <link:definitionArc order="35" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_7730440095C4F9BA5AE55B4F0AC6D991" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_6B51EF84AD7B4A6EA26F5B4F0AC6C533" xlink:type="locator" />
    <link:definitionArc order="36" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_6B51EF84AD7B4A6EA26F5B4F0AC6C533" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_3ABBE8ABD94BCCDE1CC75B4F0AC61168" xlink:type="locator" />
    <link:definitionArc order="37" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_26E154371994030290395B4F0AC60639" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_3ABBE8ABD94BCCDE1CC75B4F0AC61168" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RegulatoryCapitalRequirementsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RevenueFromContractsWithCustomers" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RevenueFromContractsWithCustomersDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_71DE742400813227D0F3C95C97B22B43" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_71DE742400813227D0F3C95C97B22B43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_AE867AEC2117585E793DC95C97B2A268_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_71DE742400813227D0F3C95C97B22B43" xlink:to="loc_us-gaap_SegmentDomain_AE867AEC2117585E793DC95C97B2A268_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_AE867AEC2117585E793DC95C97B2A268" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_71DE742400813227D0F3C95C97B22B43" xlink:to="loc_us-gaap_SegmentDomain_AE867AEC2117585E793DC95C97B2A268" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_12D6756B43A6A27BD7EDC95C97B25DD1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_srt_ProductOrServiceAxis_12D6756B43A6A27BD7EDC95C97B25DD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_83E1475F0FA33E663DCCC95C97B2F650_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_12D6756B43A6A27BD7EDC95C97B25DD1" xlink:to="loc_srt_ProductsAndServicesDomain_83E1475F0FA33E663DCCC95C97B2F650_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_83E1475F0FA33E663DCCC95C97B2F650" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_12D6756B43A6A27BD7EDC95C97B25DD1" xlink:to="loc_srt_ProductsAndServicesDomain_83E1475F0FA33E663DCCC95C97B2F650" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_03B2FDACCEE1CE8BF4E8C95C97B20B69" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_srt_StatementGeographicalAxis_03B2FDACCEE1CE8BF4E8C95C97B20B69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_258F1B0B61912F2E6F2EC95C97B29667_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_03B2FDACCEE1CE8BF4E8C95C97B20B69" xlink:to="loc_srt_SegmentGeographicalDomain_258F1B0B61912F2E6F2EC95C97B29667_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_258F1B0B61912F2E6F2EC95C97B29667" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_03B2FDACCEE1CE8BF4E8C95C97B20B69" xlink:to="loc_srt_SegmentGeographicalDomain_258F1B0B61912F2E6F2EC95C97B29667" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_E62430719B065A995582C95C97B2933D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_E62430719B065A995582C95C97B2933D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_AA3B2F8873E9CD13E6A4C95C97B2E599_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_E62430719B065A995582C95C97B2933D" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_AA3B2F8873E9CD13E6A4C95C97B2E599_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_AA3B2F8873E9CD13E6A4C95C97B2E599" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_E62430719B065A995582C95C97B2933D" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_AA3B2F8873E9CD13E6A4C95C97B2E599" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerDurationAxis" xlink:label="loc_us-gaap_ContractWithCustomerDurationAxis_81AAA91CD72D006E4C8EC95C97B22236" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_us-gaap_ContractWithCustomerDurationAxis_81AAA91CD72D006E4C8EC95C97B22236" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerDurationDomain" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_B92E0207E638690868DCC95C97B2012A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_81AAA91CD72D006E4C8EC95C97B22236" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_B92E0207E638690868DCC95C97B2012A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerDurationDomain" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_B92E0207E638690868DCC95C97B2012A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_81AAA91CD72D006E4C8EC95C97B22236" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_B92E0207E638690868DCC95C97B2012A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_D4E66C442778AF3DA352C95C97B2CD0E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_D4E66C442778AF3DA352C95C97B2CD0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9D06017D512AE6B1A3C0C95C97B248D9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_D4E66C442778AF3DA352C95C97B2CD0E" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9D06017D512AE6B1A3C0C95C97B248D9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9D06017D512AE6B1A3C0C95C97B248D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_D4E66C442778AF3DA352C95C97B2CD0E" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9D06017D512AE6B1A3C0C95C97B248D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4AB82CE571D16EC54FA1C95C97B25BF9" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4AB82CE571D16EC54FA1C95C97B25BF9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_DD7A115B2E7B62FCFF7FC95C97B206A7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4AB82CE571D16EC54FA1C95C97B25BF9" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_DD7A115B2E7B62FCFF7FC95C97B206A7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_DD7A115B2E7B62FCFF7FC95C97B206A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4AB82CE571D16EC54FA1C95C97B25BF9" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_DD7A115B2E7B62FCFF7FC95C97B206A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_7C3D54A38ACF835584BDC95C97B268C2" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_BED5DCCE11D4C0FAE037C95C97A2F5F6" xlink:to="loc_srt_MajorCustomersAxis_7C3D54A38ACF835584BDC95C97B268C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_F56E35FB6EE6D72B459CC95C97B2B95B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_7C3D54A38ACF835584BDC95C97B268C2" xlink:to="loc_srt_NameOfMajorCustomerDomain_F56E35FB6EE6D72B459CC95C97B2B95B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_F56E35FB6EE6D72B459CC95C97B2B95B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_7C3D54A38ACF835584BDC95C97B268C2" xlink:to="loc_srt_NameOfMajorCustomerDomain_F56E35FB6EE6D72B459CC95C97B2B95B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Depositaccountandtreasurymanagementfees" xlink:label="loc_colb_Depositaccountandtreasurymanagementfees_F280115009481FB4F76BC95C97B2DC81" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_colb_Depositaccountandtreasurymanagementfees_F280115009481FB4F76BC95C97B2DC81" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Cardrevenue" xlink:label="loc_colb_Cardrevenue_90F3948567D218ECBDAAC95C97B2431B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_colb_Cardrevenue_90F3948567D218ECBDAAC95C97B2431B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Financialservicesandtrustrevenue" xlink:label="loc_colb_Financialservicesandtrustrevenue_BC3EEBE9F96BF41D79A6C95C97B2070F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_colb_Financialservicesandtrustrevenue_BC3EEBE9F96BF41D79A6C95C97B2070F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Revenuefromcontractswithcustomers" xlink:label="loc_colb_Revenuefromcontractswithcustomers_CC4B2D1A45BD16A4EEB7C95C97B25C68" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_colb_Revenuefromcontractswithcustomers_CC4B2D1A45BD16A4EEB7C95C97B25C68" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Noninterestincomeexcludingrevenuefromcontractswithcustomers" xlink:label="loc_colb_Noninterestincomeexcludingrevenuefromcontractswithcustomers_58C81311BA1E7985DC2AC95C97B219E9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_colb_Noninterestincomeexcludingrevenuefromcontractswithcustomers_58C81311BA1E7985DC2AC95C97B219E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncome" xlink:label="loc_us-gaap_NoninterestIncome_23D03AD4F14D1940E622C95C97B2D44D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F069C8B7DE535501DEEEC95C97B23F7E" xlink:to="loc_us-gaap_NoninterestIncome_23D03AD4F14D1940E622C95C97B2D44D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/RevenueFromContractsWithCustomersTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/Securities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesCarryingValueOfSecuritiesPledgedAsCollateralDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7DA9C55BC6A8B9EB52FB5C485835BF32" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_A5C9080D849AD434AACA5C485835D977" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7DA9C55BC6A8B9EB52FB5C485835BF32" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_A5C9080D849AD434AACA5C485835D977" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuritiesPledgedAsCollateralByCounterpartyAxis" xlink:label="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyAxis_F7EDF7BC7DFDAED4C4285C4858352A80" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_A5C9080D849AD434AACA5C485835D977" xlink:to="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyAxis_F7EDF7BC7DFDAED4C4285C4858352A80" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuritiesPledgedAsCollateralByCounterpartyDomain" xlink:label="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyAxis_F7EDF7BC7DFDAED4C4285C4858352A80" xlink:to="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SecuritiesPledgedAsCollateralByCounterpartyDomain" xlink:label="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyAxis_F7EDF7BC7DFDAED4C4285C4858352A80" xlink:to="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_WashingtonAndOregonStatePublicDepositsMember" xlink:label="loc_colb_WashingtonAndOregonStatePublicDepositsMember_7E98C4A0A1D25A1AE9125C485835EA24" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC" xlink:to="loc_colb_WashingtonAndOregonStatePublicDepositsMember_7E98C4A0A1D25A1AE9125C485835EA24" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalReserveBankAdvancesMember" xlink:label="loc_us-gaap_FederalReserveBankAdvancesMember_D0D23EA19F01F7F43E665C485835CD1A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC" xlink:to="loc_us-gaap_FederalReserveBankAdvancesMember_D0D23EA19F01F7F43E665C485835CD1A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSecuritiesMember" xlink:label="loc_colb_OtherSecuritiesMember_43EB93FA1FDDACFD51645C485835134D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_SecuritiesPledgedAsCollateralByCounterpartyDomain_C118F63A44E962067C395C485835ACBC" xlink:to="loc_colb_OtherSecuritiesMember_43EB93FA1FDDACFD51645C485835134D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRestricted" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_5BA0FD4A361AFE93143E5C4858355960" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7DA9C55BC6A8B9EB52FB5C485835BF32" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRestricted_5BA0FD4A361AFE93143E5C4858355960" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_C53BBAA0067574CE0FC3B9FB9EA92E6B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_C53BBAA0067574CE0FC3B9FB9EA92E6B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_9D4E394F895178611894B9FB9EACDBA5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_C53BBAA0067574CE0FC3B9FB9EA92E6B" xlink:to="loc_us-gaap_FinancialInstrumentAxis_9D4E394F895178611894B9FB9EACDBA5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_9D4E394F895178611894B9FB9EACDBA5" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_9D4E394F895178611894B9FB9EACDBA5" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_25C047EA14F13608674BB9FB9EACE069" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_25C047EA14F13608674BB9FB9EACE069" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSecuritiesMember" xlink:label="loc_colb_OtherSecuritiesMember_1C7CBFB2887EF87A8416B9FB9EACA95B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:to="loc_colb_OtherSecuritiesMember_1C7CBFB2887EF87A8416B9FB9EACA95B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember" xlink:label="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_409A8EAAA8361872EC29B9FB9EAC9A08" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:to="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_409A8EAAA8361872EC29B9FB9EAC9A08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="loc_us-gaap_MunicipalBondsMember_80F7F3012CC62E4AA13FB9FB9EACEEFC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:to="loc_us-gaap_MunicipalBondsMember_80F7F3012CC62E4AA13FB9FB9EACEEFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_83D9B7121EF9B803BA74B9FB9EAC9067" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_723601B5A15C5FC82620B9FB9EAC73D2" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_83D9B7121EF9B803BA74B9FB9EAC9067" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfIssuancesOfSecuritiesExceedingShareholdersEquityThreshold" xlink:label="loc_colb_NumberOfIssuancesOfSecuritiesExceedingShareholdersEquityThreshold_9195E3AC00295A985CC1B9FB9EAC9369" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_colb_NumberOfIssuancesOfSecuritiesExceedingShareholdersEquityThreshold_9195E3AC00295A985CC1B9FB9EAC9369" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_AACFD0509EE9112E73D5B9FB9EACE66B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_AACFD0509EE9112E73D5B9FB9EACE66B" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfSecuritiesInUnrealizedLossPosition" xlink:label="loc_colb_NumberOfSecuritiesInUnrealizedLossPosition_08925F8E7971937BAFC2B9FB9EAC9B63" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_colb_NumberOfSecuritiesInUnrealizedLossPosition_08925F8E7971937BAFC2B9FB9EAC9B63" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfSecuritiesInContinuousLossPositionForTwelveMonthsOrMore" xlink:label="loc_colb_NumberOfSecuritiesInContinuousLossPositionForTwelveMonthsOrMore_6C8354F62A7E059588EBB9FB9EACAF2C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_colb_NumberOfSecuritiesInContinuousLossPositionForTwelveMonthsOrMore_6C8354F62A7E059588EBB9FB9EACAF2C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_IssuancesOfSecuritiesExceedingShareholdersEquityThresholdPercent" xlink:label="loc_colb_IssuancesOfSecuritiesExceedingShareholdersEquityThresholdPercent_E53F480A79B52844D8BBB9FB9EAECAD3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5B336C6C6AED70BCB5F6B9FB9EAC2FE1" xlink:to="loc_colb_IssuancesOfSecuritiesExceedingShareholdersEquityThresholdPercent_E53F480A79B52844D8BBB9FB9EAECAD3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesScheduleOfContractualMaturitiesOfInvestmentSecuritiesAvailableForSaleDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSecuritiesAvailableForSaleDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_8381F35E2AAE84F6BDF1750FFF677AA7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_8381F35E2AAE84F6BDF1750FFF677AA7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_3C2772D030282230AD10750FFF67DD6F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_8381F35E2AAE84F6BDF1750FFF677AA7" xlink:to="loc_us-gaap_FinancialInstrumentAxis_3C2772D030282230AD10750FFF67DD6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_3C2772D030282230AD10750FFF67DD6F" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_3C2772D030282230AD10750FFF67DD6F" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember" xlink:label="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_B2852A8856D6AE17185C750FFF68652A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:to="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_B2852A8856D6AE17185C750FFF68652A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="loc_us-gaap_MunicipalBondsMember_6AD2E3B7401371977BCF750FFF685CDB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:to="loc_us-gaap_MunicipalBondsMember_6AD2E3B7401371977BCF750FFF685CDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_0CB5B4BDE17AF6916F6A750FFF68348C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_0CB5B4BDE17AF6916F6A750FFF68348C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_6430C7071BA9B48C787A750FFF686EAB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_6430C7071BA9B48C787A750FFF686EAB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSecuritiesMember" xlink:label="loc_colb_OtherSecuritiesMember_6930E1AA531C787A166F750FFF6874AA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_97246FED6D0839D8FAAF750FFF67A0FE" xlink:to="loc_colb_OtherSecuritiesMember_6930E1AA531C787A166F750FFF6874AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAmortizedCost_334AA94420B2467CEDEB750FFF6911B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAmortizedCost_334AA94420B2467CEDEB750FFF6911B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_72392636EB3EE1BC106F750FFF694546" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_72392636EB3EE1BC106F750FFF694546" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_8A284DA085CB1D2C1593750FFF69C7CD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_8A284DA085CB1D2C1593750FFF69C7CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecurities_D2264F32ADD19869A807750FFF69FDC1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_BB751606565DCFCF44F9750FFF6829A2" xlink:to="loc_us-gaap_AvailableForSaleSecurities_D2264F32ADD19869A807750FFF69FDC1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSecuritiesSummaryOfGrossRealizedGainsAndLossesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchase" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchaseDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable" xlink:label="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_6329DB7A7CF98DE5E033F285DF08BE92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_6329DB7A7CF98DE5E033F285DF08BE92" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_E97546B583F8B96E3E9CF285DF18B14D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_6329DB7A7CF98DE5E033F285DF08BE92" xlink:to="loc_us-gaap_DebtInstrumentAxis_E97546B583F8B96E3E9CF285DF18B14D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7F264C01EDE6E95EDAA5F285DF18BD01_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_E97546B583F8B96E3E9CF285DF18B14D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7F264C01EDE6E95EDAA5F285DF18BD01_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7F264C01EDE6E95EDAA5F285DF18BD01" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_E97546B583F8B96E3E9CF285DF18B14D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7F264C01EDE6E95EDAA5F285DF18BD01" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RepurchaseAgreementsSweepMember" xlink:label="loc_colb_RepurchaseAgreementsSweepMember_8DCD1734AC180A3148BEF285DF1838B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7F264C01EDE6E95EDAA5F285DF18BD01" xlink:to="loc_colb_RepurchaseAgreementsSweepMember_8DCD1734AC180A3148BEF285DF1838B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_147676ACBA0C5C78A189F285DF18646A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_6329DB7A7CF98DE5E033F285DF08BE92" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_147676ACBA0C5C78A189F285DF18646A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_3EBFC29A4A86E87D172EF285DF18DF52_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_147676ACBA0C5C78A189F285DF18646A" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_3EBFC29A4A86E87D172EF285DF18DF52_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_3EBFC29A4A86E87D172EF285DF18DF52" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_147676ACBA0C5C78A189F285DF18646A" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_3EBFC29A4A86E87D172EF285DF18DF52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember_F001F779A364A90A9D63F285DF18D3E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_3EBFC29A4A86E87D172EF285DF18DF52" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesMember_F001F779A364A90A9D63F285DF18D3E7" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount_757BBB5E9D1298BA49E3F285DF187A11" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermCarryingAmount_757BBB5E9D1298BA49E3F285DF187A11" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseTermInterestrate" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermInterestrate_008189685EBAF4048D30F285DF187515" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseTermInterestrate_008189685EBAF4048D30F285DF187515" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount_702CBD95A2A60AE2ED71F285DF18E4C1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepCarryingAmount_702CBD95A2A60AE2ED71F285DF18E4C1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AssetsSoldunderAgreementstoRepurchaseSweepInterestrate" xlink:label="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepInterestrate_D072C86FFBD77B9B9C10F285DF18CA99" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_colb_AssetsSoldunderAgreementstoRepurchaseSweepInterestrate_D072C86FFBD77B9B9C10F285DF18CA99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements" xlink:label="loc_us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements_9A99BF8E183176837C4DF285DF181125" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_67C7A8C73383C9A2BDBDF285DF1871BA" xlink:to="loc_us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements_9A99BF8E183176837C4DF285DF181125" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSoldUnderAgreementsToRepurchaseTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesSummaryOfGrossUnrealizedLossesAndFairValueOfInvestmentsWithUnrealizedLossesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_F1276EE09B66EE61438EA5D5371C1DAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_F1276EE09B66EE61438EA5D5371C1DAC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_CEE60C082A4F74950BBCA5D5371CE1B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_F1276EE09B66EE61438EA5D5371C1DAC" xlink:to="loc_us-gaap_FinancialInstrumentAxis_CEE60C082A4F74950BBCA5D5371CE1B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_CEE60C082A4F74950BBCA5D5371CE1B9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_CEE60C082A4F74950BBCA5D5371CE1B9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember" xlink:label="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_8B7C3DBE62E93DD5BAECA5D5371C8C11" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:to="loc_colb_USGovernmentAgencyAndGovernmentSponsoredEnterpriseMortgageBackedSecuritiesAndCollateralizedMortgageObligationsMember_8B7C3DBE62E93DD5BAECA5D5371C8C11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="loc_us-gaap_MunicipalBondsMember_D4DE83B81C30439FF5DFA5D5371CD211" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:to="loc_us-gaap_MunicipalBondsMember_D4DE83B81C30439FF5DFA5D5371CD211" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_55BECB12850ED2CCF5B8A5D5371C88DD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_55BECB12850ED2CCF5B8A5D5371C88DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_6F9F0018C49161D43D09A5D5371C0622" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_6F9F0018C49161D43D09A5D5371C0622" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_OtherSecuritiesMember" xlink:label="loc_colb_OtherSecuritiesMember_874428254BDFB23377D0A5D5371CBA32" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_CD03CE552790CC4C8DF9A5D5371CB0EE" xlink:to="loc_colb_OtherSecuritiesMember_874428254BDFB23377D0A5D5371CBA32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNiGainLoss" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_AB4E86C8BF69FF28F5EEA5D63FB12A49" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_AB4E86C8BF69FF28F5EEA5D63FB12A49" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNiRealizedGainLoss" xlink:label="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_E20C5A354C58B024844AA5DC23C9E80A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_E20C5A354C58B024844AA5DC23C9E80A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_AFFB241171EFAD812E34A5D5371C374E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_AFFB241171EFAD812E34A5D5371C374E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessthan12MonthsAggregateLossInstant" xlink:label="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessthan12MonthsAggregateLossInstant_800BF8BDD72A5B261103A5D5371CA11C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessthan12MonthsAggregateLossInstant_800BF8BDD72A5B261103A5D5371CA11C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_C071728C858646A0A450A5D5371C68F0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_C071728C858646A0A450A5D5371C68F0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsorLongerAggregateLossinstant" xlink:label="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsorLongerAggregateLossinstant_B3A751CC7128EDCC956CA5D5371C42AD" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsorLongerAggregateLossinstant_B3A751CC7128EDCC956CA5D5371C42AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_A89C94060495EFEAABFCA5D5371C72EC" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_A89C94060495EFEAABFCA5D5371C72EC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLossinstant" xlink:label="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLossinstant_2DE5FA542C3BAF898624A5D5371CFFB1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_colb_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLossinstant_2DE5FA542C3BAF898624A5D5371CFFB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:label="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_CB0459A5E69F58B141F6A5ECF9D28752" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0B35B99FE6005E012115A5D5371C802A" xlink:to="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_CB0459A5E69F58B141F6A5ECF9D28752" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SecuritiesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_07714CC2BE4423EA0E43C95C43B059F2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_25F031DC8199FB081F7CC95C43AE8010" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_07714CC2BE4423EA0E43C95C43B059F2" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_25F031DC8199FB081F7CC95C43AE8010" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_90594A39AF3EB39E3746C95C43AF74C3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_25F031DC8199FB081F7CC95C43AE8010" xlink:to="loc_us-gaap_FinancialInstrumentAxis_90594A39AF3EB39E3746C95C43AF74C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B36F4A37AF6A1F878683C95C43AF2CEB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_90594A39AF3EB39E3746C95C43AF74C3" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B36F4A37AF6A1F878683C95C43AF2CEB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B36F4A37AF6A1F878683C95C43AF2CEB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_90594A39AF3EB39E3746C95C43AF74C3" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_B36F4A37AF6A1F878683C95C43AF2CEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_CA2C488FDD19B293A939C95C43AF01E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_25F031DC8199FB081F7CC95C43AE8010" xlink:to="loc_srt_RangeAxis_CA2C488FDD19B293A939C95C43AF01E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_FCA646D22B3EB5878A77C95C43AFDF71_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_CA2C488FDD19B293A939C95C43AF01E4" xlink:to="loc_srt_RangeMember_FCA646D22B3EB5878A77C95C43AFDF71_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_FCA646D22B3EB5878A77C95C43AFDF71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_CA2C488FDD19B293A939C95C43AF01E4" xlink:to="loc_srt_RangeMember_FCA646D22B3EB5878A77C95C43AFDF71" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareBasedPayments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareBasedPaymentsShareAwardsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareBasedPaymentsShareOptionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A2022D17BB43C7AEADACA625E854CF61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A2022D17BB43C7AEADACA625E854CF61" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_9838528BD299D27BDFF8A625E855FBA4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A2022D17BB43C7AEADACA625E854CF61" xlink:to="loc_us-gaap_AwardTypeAxis_9838528BD299D27BDFF8A625E855FBA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_FD73A6546ACC78C89CC7A625E8555330_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_9838528BD299D27BDFF8A625E855FBA4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_FD73A6546ACC78C89CC7A625E8555330_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_FD73A6546ACC78C89CC7A625E8555330" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_9838528BD299D27BDFF8A625E855FBA4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_FD73A6546ACC78C89CC7A625E8555330" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockOptionMember" xlink:label="loc_us-gaap_StockOptionMember_B12A44EAC8A46D5CC618A625E8552348" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_FD73A6546ACC78C89CC7A625E8555330" xlink:to="loc_us-gaap_StockOptionMember_B12A44EAC8A46D5CC618A625E8552348" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_B20781AFF0B1599A1ACAA625E8554BF6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A2022D17BB43C7AEADACA625E854CF61" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_B20781AFF0B1599A1ACAA625E8554BF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_B20781AFF0B1599A1ACAA625E8554BF6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_B20781AFF0B1599A1ACAA625E8554BF6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom0.00To9.99Member" xlink:label="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom0.00To9.99Member_A155102EDACB485F41D2A625E856F382" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8" xlink:to="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom0.00To9.99Member_A155102EDACB485F41D2A625E856F382" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom40.00To49.99MemberMember" xlink:label="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom40.00To49.99MemberMember_B4BD3255336618D7E7C6A625E8568CD3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8" xlink:to="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom40.00To49.99MemberMember_B4BD3255336618D7E7C6A625E8568CD3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom50.00To136.93Member" xlink:label="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom50.00To136.93Member_18B418AF215E7BDD31A0A625E856CB98" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2645E971A7A026CACF6AA625E8569CE8" xlink:to="loc_colb_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeFrom50.00To136.93Member_18B418AF215E7BDD31A0A625E856CB98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_2B2F5A385E1BE918B576A625E8578F01" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_2B2F5A385E1BE918B576A625E8578F01" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisablePeriod" xlink:label="loc_colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisablePeriod_953B93E2BC1B77D66B57A625E857EF4A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisablePeriod_953B93E2BC1B77D66B57A625E857EF4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3E3A150C71F2EF4CB693A625E8573DD1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3E3A150C71F2EF4CB693A625E8573DD1" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumTerm" xlink:label="loc_colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumTerm_14E3CEBDC99874229CFCA625E857EA2F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_colb_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumTerm_14E3CEBDC99874229CFCA625E857EA2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_B0BEF12B3F19EC3D7DDFA625E858EC53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_B0BEF12B3F19EC3D7DDFA625E858EC53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_50E192461AB360455D92A625E858681B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_50E192461AB360455D92A625E858681B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_53C8D0104C7D993ACC13A625E8598A9C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_53C8D0104C7D993ACC13A625E8598A9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_B97AAE0E3E41F43BEE8BA625E85963C0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_B97AAE0E3E41F43BEE8BA625E85963C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_FF150A9C2D2F897FD2DCA625E85923B0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_FF150A9C2D2F897FD2DCA625E85923B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_42510737CBE84651B220A625E8594F0A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_42510737CBE84651B220A625E8594F0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_3893E2203B12D89F3830A625E859D040" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_3893E2203B12D89F3830A625E859D040" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_AE80C6D784CB1AD383CEA625E8591F64" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_AE80C6D784CB1AD383CEA625E8591F64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_14875D530F01CF3BD181A625E85A3944" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_14875D530F01CF3BD181A625E85A3944" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_51BCAA121A2E2304C7B5A625E85A7EBF" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_51BCAA121A2E2304C7B5A625E85A7EBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_21A0E6D4708AEB80929FA625E85A70CD" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_21A0E6D4708AEB80929FA625E85A70CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_75C3A545D562D2D6278EA625E85A7220" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_75C3A545D562D2D6278EA625E85A7220" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_6103C674290A8CE10303A625E85B9058" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_6103C674290A8CE10303A625E85B9058" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_1E13ACDCBC066331066EA625E85BE9BC" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_1E13ACDCBC066331066EA625E85BE9BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_B03342E9B8A45E79B03AA625E85B2C4E" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_B03342E9B8A45E79B03AA625E85B2C4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_0B37ECCA012EFF16B359A625E85BCFD9" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_0B37ECCA012EFF16B359A625E85BCFD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_C7C4598263D3B3836ECFA625E85BCE8D" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_33A736A4967C47A78B75A625E8584922" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_C7C4598263D3B3836ECFA625E85BCE8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_D0C397644E61D211CE9AA625E85B67B0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_D0C397644E61D211CE9AA625E85B67B0" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract" xlink:label="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_B5C11DDEB7A728117090A625E85CD350" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_B5C11DDEB7A728117090A625E85CD350" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4725299F6F2EEFA6E21AA625E85CCDE9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4725299F6F2EEFA6E21AA625E85CCDE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_4625C39EF1704D96C2C1A625E85C09A3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_4625C39EF1704D96C2C1A625E85C09A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_27ED8EBDBB763105211AA625E85C2869" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_27ED8EBDBB763105211AA625E85C2869" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_26C94CD2C5C60B243983A625E85D2977" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_26C94CD2C5C60B243983A625E85D2977" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_124DC81AA4FB599808D6A625E85D1119" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_124DC81AA4FB599808D6A625E85D1119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_7BC6D946C53C8E1FFAA7A625E85D5AC9" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract_6506B3E7703B055EF444A625E85C8737" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_7BC6D946C53C8E1FFAA7A625E85D5AC9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_54D349D86AD447981BDAA625E85D3527" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_ShareBasedCompensation_54D349D86AD447981BDAA625E85D3527" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_E28272D86FE3752CAE30A625E85DCC43" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_FE351857D4700367FA3DA625E856EEE5" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_E28272D86FE3752CAE30A625E85DCC43" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareBasedPaymentsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareholdersEquity" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_03928CF75875C119FAD0F29DA3A54486" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_A2CBB0DEEB2AD5F9EA2AF29DA3A26554" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_03928CF75875C119FAD0F29DA3A54486" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_A2CBB0DEEB2AD5F9EA2AF29DA3A26554" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9B3A513ECC79F361FAAFF29DA3A38E2D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_A2CBB0DEEB2AD5F9EA2AF29DA3A26554" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9B3A513ECC79F361FAAFF29DA3A38E2D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_01CC1F597F16BF3EF922F29DA3A3AC97_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9B3A513ECC79F361FAAFF29DA3A38E2D" xlink:to="loc_us-gaap_EquityComponentDomain_01CC1F597F16BF3EF922F29DA3A3AC97_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_01CC1F597F16BF3EF922F29DA3A3AC97" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9B3A513ECC79F361FAAFF29DA3A38E2D" xlink:to="loc_us-gaap_EquityComponentDomain_01CC1F597F16BF3EF922F29DA3A3AC97" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_F9A44BE723891A4738C7F29DA3A42383" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01CC1F597F16BF3EF922F29DA3A3AC97" xlink:to="loc_us-gaap_PreferredStockMember_F9A44BE723891A4738C7F29DA3A42383" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_E06FFF8249474A145076F29DA3A4B1D4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_A2CBB0DEEB2AD5F9EA2AF29DA3A26554" xlink:to="loc_us-gaap_StatementClassOfStockAxis_E06FFF8249474A145076F29DA3A4B1D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_E06FFF8249474A145076F29DA3A4B1D4" xlink:to="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_E06FFF8249474A145076F29DA3A4B1D4" xlink:to="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_2A0B1DC708568F43804EF29DA3A45C0A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928" xlink:to="loc_us-gaap_PreferredStockMember_2A0B1DC708568F43804EF29DA3A45C0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_6887EDCC0EAEB677B782F29DA3A56691" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_A5FD21673EFB663EE137F29DA3A43928" xlink:to="loc_us-gaap_CommonStockMember_6887EDCC0EAEB677B782F29DA3A56691" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_FEA8F05C6094D4A81FA2F29DA3A596C6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_A2CBB0DEEB2AD5F9EA2AF29DA3A26554" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_FEA8F05C6094D4A81FA2F29DA3A596C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_18E61FA49B20FCE1FE8EF29DA3A50C26_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_FEA8F05C6094D4A81FA2F29DA3A596C6" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_18E61FA49B20FCE1FE8EF29DA3A50C26_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_18E61FA49B20FCE1FE8EF29DA3A50C26" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_FEA8F05C6094D4A81FA2F29DA3A596C6" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_18E61FA49B20FCE1FE8EF29DA3A50C26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_08CF2F8A6567CA2AD13CF29DA3A5E4AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_18E61FA49B20FCE1FE8EF29DA3A50C26" xlink:to="loc_us-gaap_SubsequentEventMember_08CF2F8A6567CA2AD13CF29DA3A5E4AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_938D314DADFB9C3015F7F29DA3A6705C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_03928CF75875C119FAD0F29DA3A54486" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_938D314DADFB9C3015F7F29DA3A6705C" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_CommonStockSpecialCashDividendsPerShareDeclared" xlink:label="loc_colb_CommonStockSpecialCashDividendsPerShareDeclared_DEC143C6A28D56BEAB18F29DA3A6CA48" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_03928CF75875C119FAD0F29DA3A54486" xlink:to="loc_colb_CommonStockSpecialCashDividendsPerShareDeclared_DEC143C6A28D56BEAB18F29DA3A6CA48" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/ShareholdersEquityDividendsDeclaredTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubordinatedDebentures" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingLineItems" xlink:label="loc_us-gaap_SubordinatedBorrowingLineItems_2E827B92748C75833A845B4F08850C0C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingTable" xlink:label="loc_us-gaap_SubordinatedBorrowingTable_B1A57A53FCDFD6CDF6C75B4F0885067B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_2E827B92748C75833A845B4F08850C0C" xlink:to="loc_us-gaap_SubordinatedBorrowingTable_B1A57A53FCDFD6CDF6C75B4F0885067B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingAxis" xlink:label="loc_us-gaap_SubordinatedBorrowingAxis_0E011D8AC98D0A7A042E5B4F0885D557" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubordinatedBorrowingTable_B1A57A53FCDFD6CDF6C75B4F0885067B" xlink:to="loc_us-gaap_SubordinatedBorrowingAxis_0E011D8AC98D0A7A042E5B4F0885D557" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingNameDomain" xlink:label="loc_us-gaap_SubordinatedBorrowingNameDomain_9C312E7B1B1C3BD5481D5B4F08859BF5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubordinatedBorrowingAxis_0E011D8AC98D0A7A042E5B4F0885D557" xlink:to="loc_us-gaap_SubordinatedBorrowingNameDomain_9C312E7B1B1C3BD5481D5B4F08859BF5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingNameDomain" xlink:label="loc_us-gaap_SubordinatedBorrowingNameDomain_9C312E7B1B1C3BD5481D5B4F08859BF5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubordinatedBorrowingAxis_0E011D8AC98D0A7A042E5B4F0885D557" xlink:to="loc_us-gaap_SubordinatedBorrowingNameDomain_9C312E7B1B1C3BD5481D5B4F08859BF5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingsDisclosureTextBlock" xlink:label="loc_us-gaap_SubordinatedBorrowingsDisclosureTextBlock_431D64AF91A63D57683B5B4F08851B5A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_2E827B92748C75833A845B4F08850C0C" xlink:to="loc_us-gaap_SubordinatedBorrowingsDisclosureTextBlock_431D64AF91A63D57683B5B4F08851B5A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubordinatedDebenturesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingLineItems" xlink:label="loc_us-gaap_SubordinatedBorrowingLineItems_33A78C05E9472848CA545B4F0856C057" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingTable" xlink:label="loc_us-gaap_SubordinatedBorrowingTable_B1B7325F83BBE511ECF45B4F0856E1A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_33A78C05E9472848CA545B4F0856C057" xlink:to="loc_us-gaap_SubordinatedBorrowingTable_B1B7325F83BBE511ECF45B4F0856E1A3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingAxis" xlink:label="loc_us-gaap_SubordinatedBorrowingAxis_642B553FDAD60D0132A95B4F0856E905" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubordinatedBorrowingTable_B1B7325F83BBE511ECF45B4F0856E1A3" xlink:to="loc_us-gaap_SubordinatedBorrowingAxis_642B553FDAD60D0132A95B4F0856E905" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingNameDomain" xlink:label="loc_us-gaap_SubordinatedBorrowingNameDomain_8E093741CC094D9777A05B4F0856393A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubordinatedBorrowingAxis_642B553FDAD60D0132A95B4F0856E905" xlink:to="loc_us-gaap_SubordinatedBorrowingNameDomain_8E093741CC094D9777A05B4F0856393A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingNameDomain" xlink:label="loc_us-gaap_SubordinatedBorrowingNameDomain_8E093741CC094D9777A05B4F0856393A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubordinatedBorrowingAxis_642B553FDAD60D0132A95B4F0856E905" xlink:to="loc_us-gaap_SubordinatedBorrowingNameDomain_8E093741CC094D9777A05B4F0856393A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5EE0BB31AAF96BBD36385B4F0856DD83" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubordinatedBorrowingTable_B1B7325F83BBE511ECF45B4F0856E1A3" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5EE0BB31AAF96BBD36385B4F0856DD83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6510E6F0746414FB26555B4F08564924_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5EE0BB31AAF96BBD36385B4F0856DD83" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6510E6F0746414FB26555B4F08564924_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6510E6F0746414FB26555B4F08564924" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5EE0BB31AAF96BBD36385B4F0856DD83" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6510E6F0746414FB26555B4F08564924" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PacificContinentalMember" xlink:label="loc_colb_PacificContinentalMember_7A23E729EBDA3555656F5B4F08561CC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6510E6F0746414FB26555B4F08564924" xlink:to="loc_colb_PacificContinentalMember_7A23E729EBDA3555656F5B4F08561CC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_AF379C34DA049597597E5B4F08569AC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_33A78C05E9472848CA545B4F0856C057" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_AF379C34DA049597597E5B4F08569AC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedBorrowingInterestRate" xlink:label="loc_us-gaap_SubordinatedBorrowingInterestRate_EB1F299A2EE81FB8BA815B4F0856FC37" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_33A78C05E9472848CA545B4F0856C057" xlink:to="loc_us-gaap_SubordinatedBorrowingInterestRate_EB1F299A2EE81FB8BA815B4F0856FC37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentInterestRateTerms" xlink:label="loc_us-gaap_DebtInstrumentInterestRateTerms_3EED5DA6725A19B00A755B4F0856FE82" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubordinatedBorrowingLineItems_33A78C05E9472848CA545B4F0856C057" xlink:to="loc_us-gaap_DebtInstrumentInterestRateTerms_3EED5DA6725A19B00A755B4F0856FE82" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubordinatedDebenturesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubsequentEvents" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_72C7F3662C443569F59C0C308566AAA4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_F9EA5A1604DFDCEE0A550C308562CD23" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_72C7F3662C443569F59C0C308566AAA4" xlink:to="loc_us-gaap_SubsequentEventTable_F9EA5A1604DFDCEE0A550C308562CD23" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_3C16A47DE89B2E33D9710C3085640F1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_F9EA5A1604DFDCEE0A550C308562CD23" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_3C16A47DE89B2E33D9710C3085640F1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D8B80922D24227FAB5630C3085647DC8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3C16A47DE89B2E33D9710C3085640F1A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D8B80922D24227FAB5630C3085647DC8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D8B80922D24227FAB5630C3085647DC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3C16A47DE89B2E33D9710C3085640F1A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_D8B80922D24227FAB5630C3085647DC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_A17AA39BAC67F21DFC110C3085657660" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_F9EA5A1604DFDCEE0A550C308562CD23" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_A17AA39BAC67F21DFC110C3085657660" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_DBAFA11A4C05905A8E060C30856556D3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_A17AA39BAC67F21DFC110C3085657660" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_DBAFA11A4C05905A8E060C30856556D3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_DBAFA11A4C05905A8E060C30856556D3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_A17AA39BAC67F21DFC110C3085657660" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_DBAFA11A4C05905A8E060C30856556D3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_3731733C8E1EBC051A450C308565AC59" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_DBAFA11A4C05905A8E060C30856556D3" xlink:to="loc_us-gaap_SubsequentEventMember_3731733C8E1EBC051A450C308565AC59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_91D69BC3CF95E27E7D1C0C30856647B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_72C7F3662C443569F59C0C308566AAA4" xlink:to="loc_invest_DerivativeNotionalAmount_91D69BC3CF95E27E7D1C0C30856647B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:label="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_8EBDBF002B50F9A88EFF0C30E67ECE39" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_72C7F3662C443569F59C0C308566AAA4" xlink:to="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_8EBDBF002B50F9A88EFF0C30E67ECE39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_463A16DAD3546A0614F00C36196049C8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_72C7F3662C443569F59C0C308566AAA4" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_463A16DAD3546A0614F00C36196049C8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SubsequentEventsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnaudited" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnauditedDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfQuarterlyFinancialInformationUnauditedTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingPoliciesLineItems" xlink:label="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingPoliciesTable" xlink:label="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RecentdevelopmentsAxis" xlink:label="loc_colb_RecentdevelopmentsAxis_662BBB3AB242E31E41C2CE8B425E83AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_colb_RecentdevelopmentsAxis_662BBB3AB242E31E41C2CE8B425E83AE" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RecentdevelopmentsDomain" xlink:label="loc_colb_RecentdevelopmentsDomain_D366593DAED7BB9E4BE0CE8B425E92AF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_RecentdevelopmentsAxis_662BBB3AB242E31E41C2CE8B425E83AE" xlink:to="loc_colb_RecentdevelopmentsDomain_D366593DAED7BB9E4BE0CE8B425E92AF_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_RecentdevelopmentsDomain" xlink:label="loc_colb_RecentdevelopmentsDomain_D366593DAED7BB9E4BE0CE8B425E92AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_RecentdevelopmentsAxis_662BBB3AB242E31E41C2CE8B425E83AE" xlink:to="loc_colb_RecentdevelopmentsDomain_D366593DAED7BB9E4BE0CE8B425E92AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_0596AC58CE7DFF232DA3CE8B425E80AA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_0596AC58CE7DFF232DA3CE8B425E80AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_0596AC58CE7DFF232DA3CE8B425E80AA" xlink:to="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_0596AC58CE7DFF232DA3CE8B425E80AA" xlink:to="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_A26D5D02E0BE9B4E55E7CE8B425EE759" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_A26D5D02E0BE9B4E55E7CE8B425EE759" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingStandardsUpdate201802Member" xlink:label="loc_colb_AccountingStandardsUpdate201802Member_192757C3DF7E6C34ADB8CE8B425EA6C6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:to="loc_colb_AccountingStandardsUpdate201802Member_192757C3DF7E6C34ADB8CE8B425EA6C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201609Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201609Member_678F4BC7C18D7DFA55EFCE8B425EDD5A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:to="loc_us-gaap_AccountingStandardsUpdate201609Member_678F4BC7C18D7DFA55EFCE8B425EDD5A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201601Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201601Member_78A1818D6FFA3D94CD57CE8B425E3AE2" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_E9C10C79121737936216CE8B425E6FC8" xlink:to="loc_us-gaap_AccountingStandardsUpdate201601Member_78A1818D6FFA3D94CD57CE8B425E3AE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_E5275FE16A23A78ED525CE8B425E58D0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_E5275FE16A23A78ED525CE8B425E58D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_E5275FE16A23A78ED525CE8B425E58D0" xlink:to="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_E5275FE16A23A78ED525CE8B425E58D0" xlink:to="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_298674B5A0CBCB105462CE8B425E4E27" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2" xlink:to="loc_us-gaap_RetainedEarningsMember_298674B5A0CBCB105462CE8B425E4E27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_7D3D35781560AAB55CD4CE8B425EAA7F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_20D16582FFAF82842802CE8B425E1EE2" xlink:to="loc_us-gaap_CommonStockMember_7D3D35781560AAB55CD4CE8B425EAA7F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_B489F7B3D9D32FF40EF1CE8B425E2019" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_srt_RangeAxis_B489F7B3D9D32FF40EF1CE8B425E2019" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_B489F7B3D9D32FF40EF1CE8B425E2019" xlink:to="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_B489F7B3D9D32FF40EF1CE8B425E2019" xlink:to="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_0C18FAF7E4D4F7BA1DD4CE8B425EDC82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F" xlink:to="loc_srt_MinimumMember_0C18FAF7E4D4F7BA1DD4CE8B425EDC82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_442A8DCE4102A8B501FFCE8B425EE3D1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_CFB1AF2BC7AA838DEF47CE8B425E685F" xlink:to="loc_srt_MaximumMember_442A8DCE4102A8B501FFCE8B425EE3D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_DA52B26264D89C560A89CE8B425E2AFA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_DA52B26264D89C560A89CE8B425E2AFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_DA52B26264D89C560A89CE8B425E2AFA" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_DA52B26264D89C560A89CE8B425E2AFA" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_FFE6BBDACC27582EF712CE8B425E18FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_FFE6BBDACC27582EF712CE8B425E18FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_FE5908928689A4AE0D4FCE8B425EB60B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_FE5908928689A4AE0D4FCE8B425EB60B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VehiclesMember" xlink:label="loc_us-gaap_VehiclesMember_F63928353BB88900D032CE8B425E0C5F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:to="loc_us-gaap_VehiclesMember_F63928353BB88900D032CE8B425E0C5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_AD305D3E39223576BCBECE8B425E494D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5F98241E08CA29F43DEACE8B425E4088" xlink:to="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_AD305D3E39223576BCBECE8B425E494D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_A9B0F88A98A029C14757CE8B425EA1FB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_srt_StatementGeographicalAxis_A9B0F88A98A029C14757CE8B425EA1FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_A9B0F88A98A029C14757CE8B425EA1FB" xlink:to="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_A9B0F88A98A029C14757CE8B425EA1FB" xlink:to="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_WA" xlink:label="loc_stpr_WA_668CF89BA3B3D667D1A8CE8B425E58DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154" xlink:to="loc_stpr_WA_668CF89BA3B3D667D1A8CE8B425E58DC" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_OR" xlink:label="loc_stpr_OR_6E2C58280A29027D9445CE8B425E22B5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154" xlink:to="loc_stpr_OR_6E2C58280A29027D9445CE8B425E22B5" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_ID" xlink:label="loc_stpr_ID_A51BDC83608721CB7B54CE8B425ED652" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6D20425B800B1019248CCE8B425ED154" xlink:to="loc_stpr_ID_A51BDC83608721CB7B54CE8B425ED652" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_31143A91719724B7D14ACE8B425E79D1" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_D67E9B42B5BF349B5C01CE8B425E52B0" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_31143A91719724B7D14ACE8B425E79D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076456463C00830B4818CE8B425E7260_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_31143A91719724B7D14ACE8B425E79D1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076456463C00830B4818CE8B425E7260_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076456463C00830B4818CE8B425E7260" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_31143A91719724B7D14ACE8B425E79D1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076456463C00830B4818CE8B425E7260" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CoreDepositsMember" xlink:label="loc_us-gaap_CoreDepositsMember_D3F4EBC85329D5A3DA57CE8B425E554A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076456463C00830B4818CE8B425E7260" xlink:to="loc_us-gaap_CoreDepositsMember_D3F4EBC85329D5A3DA57CE8B425E554A" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ExpectedchangeinotherassetsduetoadoptionofnewASU" xlink:label="loc_colb_ExpectedchangeinotherassetsduetoadoptionofnewASU_754538CBEA9A0D7FFBD7CEC73C5D1B27" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_ExpectedchangeinotherassetsduetoadoptionofnewASU_754538CBEA9A0D7FFBD7CEC73C5D1B27" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_ExpectedchangeinotherliabilitiesduetoadoptionofnewASU" xlink:label="loc_colb_ExpectedchangeinotherliabilitiesduetoadoptionofnewASU_A46C576E918A62F50730CED0B520858F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_ExpectedchangeinotherliabilitiesduetoadoptionofnewASU_A46C576E918A62F50730CED0B520858F" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FHLBmembershipstockpurchaserequirementcap" xlink:label="loc_colb_FHLBmembershipstockpurchaserequirementcap_9AB4A6DDC16B48108D7FCE8B425E979E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_FHLBmembershipstockpurchaserequirementcap_9AB4A6DDC16B48108D7FCE8B425E979E" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_Gainonsaleofmerchantcardservicesportfolio" xlink:label="loc_colb_Gainonsaleofmerchantcardservicesportfolio_EC3944A532DE776518EACE8B425EF1E5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_Gainonsaleofmerchantcardservicesportfolio_EC3944A532DE776518EACE8B425EF1E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_A57B082B73A7C45D6011CE8B425E86F3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_A57B082B73A7C45D6011CE8B425E86F3" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfBranchLocations" xlink:label="loc_colb_NumberOfBranchLocations_2A7E16B40447E6A99303CE8B425F6614" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_NumberOfBranchLocations_2A7E16B40447E6A99303CE8B425F6614" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberOfDaysUsedToDetermineTreatmentAsCashEquivalent" xlink:label="loc_colb_NumberOfDaysUsedToDetermineTreatmentAsCashEquivalent_217E28D0B0729B4B37C5CE8B425F97E5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_NumberOfDaysUsedToDetermineTreatmentAsCashEquivalent_217E28D0B0729B4B37C5CE8B425F97E5" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_NumberofDaysofDelinquencyatWhichLoansAreCategorizedAsNonAccrualStatus" xlink:label="loc_colb_NumberofDaysofDelinquencyatWhichLoansAreCategorizedAsNonAccrualStatus_06A0108C052E4C274A0ACE8B425FDC60" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_NumberofDaysofDelinquencyatWhichLoansAreCategorizedAsNonAccrualStatus_06A0108C052E4C274A0ACE8B425FDC60" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansAndLeasesReceivableNonaccrualLoansConsideredImpaired" xlink:label="loc_colb_LoansAndLeasesReceivableNonaccrualLoansConsideredImpaired_42BDE52A3AA8E8F069F0CE8B425FE5CB" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_LoansAndLeasesReceivableNonaccrualLoansConsideredImpaired_42BDE52A3AA8E8F069F0CE8B425FE5CB" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansAndLeasesReceivableLoansEvaluatedForImpairmentOnQuarterlyBasisOutstanding" xlink:label="loc_colb_LoansAndLeasesReceivableLoansEvaluatedForImpairmentOnQuarterlyBasisOutstanding_8E40D194B2FBDD94D047CE8B425F63D0" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_LoansAndLeasesReceivableLoansEvaluatedForImpairmentOnQuarterlyBasisOutstanding_8E40D194B2FBDD94D047CE8B425F63D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_F965CCA4B08D1E3BFA48CE8B425FE31E" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_F965CCA4B08D1E3BFA48CE8B425FE31E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives_76758C24A1A01B9BE958CE8B425FD256" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives_76758C24A1A01B9BE958CE8B425FD256" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankstockparvalue" xlink:label="loc_colb_FederalHomeLoanBankstockparvalue_306B9F07A17FC0086239CE8B425FCD1C" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_E8A51ED60FF33F0BFC55CE8B425EFDDF" xlink:to="loc_colb_FederalHomeLoanBankstockparvalue_306B9F07A17FC0086239CE8B425FCD1C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.columbiabank.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended">
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingPoliciesLineItems" xlink:label="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:type="locator" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AccountingPoliciesTable" xlink:label="loc_colb_AccountingPoliciesTable_0568BFAA674E92CA03525B4F0A78A501" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_colb_AccountingPoliciesTable_0568BFAA674E92CA03525B4F0A78A501" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryAxis" xlink:label="loc_colb_LoansByMajorCategoryAxis_425D1A7C4A55A3F506E85B4F0A78C5DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_colb_AccountingPoliciesTable_0568BFAA674E92CA03525B4F0A78A501" xlink:to="loc_colb_LoansByMajorCategoryAxis_425D1A7C4A55A3F506E85B4F0A78C5DC" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_E6CA92AAE15A3EF66B745B4F0A789689_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_colb_LoansByMajorCategoryAxis_425D1A7C4A55A3F506E85B4F0A78C5DC" xlink:to="loc_colb_LoansByMajorCategoryDomain_E6CA92AAE15A3EF66B745B4F0A789689_default" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_LoansByMajorCategoryDomain" xlink:label="loc_colb_LoansByMajorCategoryDomain_E6CA92AAE15A3EF66B745B4F0A789689" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_colb_LoansByMajorCategoryAxis_425D1A7C4A55A3F506E85B4F0A78C5DC" xlink:to="loc_colb_LoansByMajorCategoryDomain_E6CA92AAE15A3EF66B745B4F0A789689" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_PurchasedCreditImpairedLoansMember" xlink:label="loc_colb_PurchasedCreditImpairedLoansMember_4EFFA8D55C3085191D885B4F0A787C59" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_LoansByMajorCategoryDomain_E6CA92AAE15A3EF66B745B4F0A789689" xlink:to="loc_colb_PurchasedCreditImpairedLoansMember_4EFFA8D55C3085191D885B4F0A787C59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:label="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock_2A8D8CA95326A44036405B4F0A789D5D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock_2A8D8CA95326A44036405B4F0A789D5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MarketableSecuritiesPolicy" xlink:label="loc_us-gaap_MarketableSecuritiesPolicy_5D9D9E70552DEF6D59195B4F0A785506" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_MarketableSecuritiesPolicy_5D9D9E70552DEF6D59195B4F0A785506" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_FederalHomeLoanBankStockPolicyTextBlock" xlink:label="loc_colb_FederalHomeLoanBankStockPolicyTextBlock_73305AA9663C1EE4CFF95B4F0A7868D4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_colb_FederalHomeLoanBankStockPolicyTextBlock_73305AA9663C1EE4CFF95B4F0A7868D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinanceLoansAndLeasesReceivablePolicy" xlink:label="loc_us-gaap_FinanceLoansAndLeasesReceivablePolicy_B65CE85C2640E36C0A995B4F0A78BCA4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_FinanceLoansAndLeasesReceivablePolicy_B65CE85C2640E36C0A995B4F0A78BCA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy" xlink:label="loc_us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy_225118F19FAA18D602B25B4F0A780D73" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy_225118F19FAA18D602B25B4F0A780D73" xlink:type="arc" />
    <link:loc xlink:href="colb-20181231.xsd#colb_AllowanceForUnfundedCommitmentsAndLettersOfCreditPolicyTextBlock" xlink:label="loc_colb_AllowanceForUnfundedCommitmentsAndLettersOfCreditPolicyTextBlock_51C5A8D593C9A044AA595B4F0A787E6C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_colb_AllowanceForUnfundedCommitmentsAndLettersOfCreditPolicyTextBlock_51C5A8D593C9A044AA595B4F0A787E6C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_EBD5580365BC5912DBE35B4F0A7866D5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_EBD5580365BC5912DBE35B4F0A7866D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalUseSoftwarePolicy" xlink:label="loc_us-gaap_InternalUseSoftwarePolicy_D3ABBDA7439534A890015B4F0A788F16" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_InternalUseSoftwarePolicy_D3ABBDA7439534A890015B4F0A788F16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableRealEstateAcquiredThroughForeclosurePolicy" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRealEstateAcquiredThroughForeclosurePolicy_DE61A15A86F88C5BCD385B4F0A78DBA3" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRealEstateAcquiredThroughForeclosurePolicy_DE61A15A86F88C5BCD385B4F0A78DBA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock_FBB739DE86B332C5AACE5B4F0A78A92B" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock_FBB739DE86B332C5AACE5B4F0A78A92B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="loc_us-gaap_IncomeTaxPolicyTextBlock_1FEFB2F0EFA3828E65B05B4F0A78070F" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_IncomeTaxPolicyTextBlock_1FEFB2F0EFA3828E65B05B4F0A78070F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock" xlink:label="loc_us-gaap_EarningsPerSharePolicyTextBlock_4EFD6F746AAC3B75F1AA5B4F0A7810D9" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_EarningsPerSharePolicyTextBlock_4EFD6F746AAC3B75F1AA5B4F0A7810D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost" xlink:label="loc_us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost_94ABEB5C453ADFA657065B4F0A7810AC" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost_94ABEB5C453ADFA657065B4F0A7810AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="loc_us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_CC965F96224E45DA9AFE5B4F0A788819" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_CC965F96224E45DA9AFE5B4F0A788819" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativesPolicyTextBlock" xlink:label="loc_us-gaap_DerivativesPolicyTextBlock_77972E42B8F42E1E00BF5B4F0A783E52" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_colb_AccountingPoliciesLineItems_6A0BDF37BA19CF76BAA65B4F0A78A6E8" xlink:to="loc_us-gaap_DerivativesPolicyTextBlock_77972E42B8F42E1E00BF5B4F0A783E52" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
