<?xml version="1.0" encoding="US-ASCII"?>
<!-- DFS Xcelerate Taxonomy Definition Linkbase - http://www.dfsco.com/financial-services/ -->
<!-- Version: 6.23.6 -->
<!-- Round: 8 -->
<!-- Creation date: 2017-11-09T21:32:46Z -->
<!-- Copyright (c) 2017 Donnelley Financial, LLC. All Rights Reserved. -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xbrldt="http://xbrl.org/2005/xbrldt"
  xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DocumentandEntityInformation" roleURI="http://www.nnbr.com/taxonomy/role/DocumentandEntityInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_StatementOfOtherComprehensiveIncome" roleURI="http://www.nnbr.com/taxonomy/role/StatementOfOtherComprehensiveIncome"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_StatementOfFinancialPositionClassified" roleURI="http://www.nnbr.com/taxonomy/role/StatementOfFinancialPositionClassified"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_StatementOfShareholdersEquityAndOtherComprehensiveIncome" roleURI="http://www.nnbr.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncome"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_StatementOfCashFlowsIndirect" roleURI="http://www.nnbr.com/taxonomy/role/StatementOfCashFlowsIndirect"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_StatementOfCashFlowsIndirectParen" roleURI="http://www.nnbr.com/taxonomy/role/StatementOfCashFlowsIndirectParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureInterimFinancialStatementsAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureInterimFinancialStatementsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDiscontinuedOperationsAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDiscontinuedOperationsSummaryOfMajorLineItemsIncludedInResultsOfOperationsOfDiscontinuedOperations" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfMajorLineItemsIncludedInResultsOfOperationsOfDiscontinuedOperations"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDiscontinuedOperationsSummaryOfCarryingAmountsOfMajorClassesOfAssetsAndLiabilitiesOfDiscontinuedOperations" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfCarryingAmountsOfMajorClassesOfAssetsAndLiabilitiesOfDiscontinuedOperations"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDiscontinuedOperationsSummaryOfSignificantNoncashItemsAndCashPaidForCapitalExpendituresOfDiscontinuedOperations" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfSignificantNoncashItemsAndCashPaidForCapitalExpendituresOfDiscontinuedOperations"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureInventoriesSummaryOfInventories" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureInventoriesSummaryOfInventories"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureNetIncomeLossPerShareSummaryOfNetIncomeLossPerShare" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureNetIncomeLossPerShareSummaryOfNetIncomeLossPerShare"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureNetIncomeLossPerShareAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureNetIncomeLossPerShareAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSegmentInformationSegmentInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSegmentInformationSegmentInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDebtSummaryOfDebt" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDebtSummaryOfDebt"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDebtSummaryOfDebtParenthetical" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDebtSummaryOfDebtParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureDebtAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureDebtAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureGoodwillNetChangesInCarryingAmountOfGoodwill" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureGoodwillNetChangesInCarryingAmountOfGoodwill"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureGoodwillNetAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureGoodwillNetAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureIntangibleAssetsNetSummaryOfChangesInCarryingAmountOfIntangibleAssetsNet" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureIntangibleAssetsNetSummaryOfChangesInCarryingAmountOfIntangibleAssetsNet"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureIntangibleAssetsNetAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureIntangibleAssetsNetAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSharedBasedCompensationComponentsOfShareBasedCompensationExpenseByTypeOfAward" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationComponentsOfShareBasedCompensationExpenseByTypeOfAward"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSharedBasedCompensationAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSharedBasedCompensationWeightedAverageAssumptionsRelevantToDeterminingTheFairValueAtTheDatesOfGrantAndStockOptionModification" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationWeightedAverageAssumptionsRelevantToDeterminingTheFairValueAtTheDatesOfGrantAndStockOptionModification"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSharedBasedCompensationReconciliationOfOptionActivity" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationReconciliationOfOptionActivity"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureIncomeTaxesAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureIncomeTaxesAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureCommitmentsAndContingenciesAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureInvestmentInJointVentureAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureInvestmentInJointVentureSummarizedActivityRelatedToInvestmentInJointVenture" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureSummarizedActivityRelatedToInvestmentInJointVenture"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureInvestmentInJointVentureSummarizedBalanceSheetInformationOfJointVenture" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureSummarizedBalanceSheetInformationOfJointVenture"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureFairValueMeasurementsAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureFairValueMeasurementsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesValuedOnRecurringBasis" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesValuedOnRecurringBasis"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureRestructuringAndIntegrationAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureRestructuringAndIntegrationAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureRestructuringAndIntegrationSummaryOfRestructuringAndIntegrationCharges" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureRestructuringAndIntegrationSummaryOfRestructuringAndIntegrationCharges"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfOperations" roleURI="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfOperations"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfComprehensiveIncomeLoss" roleURI="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfComprehensiveIncomeLoss"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedBalanceSheets" roleURI="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedBalanceSheets"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnChangesInStockholdersEquity" roleURI="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnChangesInStockholdersEquity"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#DisclosureSubsequentEventsAdditionalInformation" roleURI="http://www.nnbr.com/taxonomy/role/DisclosureSubsequentEventsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsQuarterlyFinancialInformationTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsQuarterlyFinancialInformationTextBlockPolicies" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlockPolicies"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsInventoryDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsInventoryDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsInventoryDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsInventoryDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsEarningsPerShareTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsEarningsPerShareTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsSegmentReportingDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDebtDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDebtDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsGoodwillDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsGoodwillDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsIncomeTaxDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsFairValueDisclosuresTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsFairValueDisclosuresTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlockTables" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="nnbr-20170930.xsd#Role_NotesToFinancialStatementsSubsequentEventsTextBlock" roleURI="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSubsequentEventsTextBlock"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DocumentandEntityInformation">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/StatementOfOtherComprehensiveIncome">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/StatementOfFinancialPositionClassified">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncome">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="us-gaap_AdditionalPaidInCapitalMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AdjustmentsRelatedToTaxWithholdingAndForfeitedForShareBasedCompensation" xlink:label="nnbr_AdjustmentsRelatedToTaxWithholdingAndForfeitedForShareBasedCompensation"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_CumulativeEffectOfInitialAdoptionOfNewAccountingPrinciples" xlink:label="nnbr_CumulativeEffectOfInitialAdoptionOfNewAccountingPrinciples"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:label="us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DividendsCommonStockCash" xlink:label="us-gaap_DividendsCommonStockCash"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="us-gaap_NoncontrollingInterestMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharesIssued" xlink:label="us-gaap_SharesIssued"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SharesPaidForTaxWithholdingAndForfeitedForShareBasedCompensation" xlink:label="nnbr_SharesPaidForTaxWithholdingAndForfeitedForShareBasedCompensation"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AdditionalPaidInCapitalMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_RetainedEarningsMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_NoncontrollingInterestMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SharesIssued" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ProfitLoss" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DividendsCommonStockCash" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="1.1300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" order="1.1400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="nnbr_AdjustmentsRelatedToTaxWithholdingAndForfeitedForShareBasedCompensation" order="1.1500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="nnbr_SharesPaidForTaxWithholdingAndForfeitedForShareBasedCompensation" order="1.1600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" order="1.1700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="nnbr_CumulativeEffectOfInitialAdoptionOfNewAccountingPrinciples" order="1.1800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/StatementOfCashFlowsIndirect">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/StatementOfCashFlowsIndirectParenthetical">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureInterimFinancialStatementsAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingStandardsUpdate201609Member" xlink:label="us-gaap_AccountingStandardsUpdate201609Member"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1" xlink:label="us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="us-gaap_EquityMethodInvesteeNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="us-gaap_EquityMethodInvesteeNameDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_InterimReportingLineItems" xlink:label="nnbr_InterimReportingLineItems"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_InterimReportingTable" xlink:label="nnbr_InterimReportingTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NorthAmericaMember" xlink:label="us-gaap_NorthAmericaMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_NumberOfManufacturingFacilities" xlink:label="nnbr_NumberOfManufacturingFacilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="us-gaap_NumberOfReportableSegments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="us-gaap_SegmentGeographicalDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="us-gaap_StatementGeographicalAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="us-gaap_TypeOfAdoptionMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="us-gaap_TypeOfAdoptionMember_2"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember" xlink:label="nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityMethodInvesteeNameDomain" xlink:to="nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_InterimReportingLineItems" xlink:to="nnbr_InterimReportingTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_InterimReportingLineItems" xlink:to="us-gaap_NumberOfReportableSegments" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_InterimReportingLineItems" xlink:to="nnbr_NumberOfManufacturingFacilities" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_InterimReportingLineItems" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_InterimReportingLineItems" xlink:to="us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_InterimReportingLineItems" xlink:to="us-gaap_PaymentsOfDebtExtinguishmentCosts" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_InterimReportingTable" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_InterimReportingTable" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_InterimReportingTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="3.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_InterimReportingTable" xlink:to="us-gaap_StatementGeographicalAxis" order="4.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="us-gaap_EquityMethodInvesteeNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="us-gaap_EquityMethodInvesteeNameDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="us-gaap_NorthAmericaMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TypeOfAdoptionMember" xlink:to="us-gaap_AccountingStandardsUpdate201609Member" order="1.0900" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnSaleOfBusiness" xlink:label="us-gaap_GainLossOnSaleOfBusiness"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PrecisionBearingComponentsSegmentMember" xlink:label="nnbr_PrecisionBearingComponentsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses" xlink:label="us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_ProceedsFromDivestitureOfBusinesses" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_GainLossOnSaleOfBusiness" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_PrecisionBearingComponentsSegmentMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain_2" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfMajorLineItemsIncludedInResultsOfOperationsOfDiscontinuedOperations">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfCarryingAmountsOfMajorClassesOfAssetsAndLiabilitiesOfDiscontinuedOperations">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDiscontinuedOperationsSummaryOfSignificantNoncashItemsAndCashPaidForCapitalExpendituresOfDiscontinuedOperations">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureInventoriesSummaryOfInventories">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureNetIncomeLossPerShareSummaryOfNetIncomeLossPerShare">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureNetIncomeLossPerShareAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_NetIncomePerShareLineItems" xlink:label="nnbr_NetIncomePerShareLineItems"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_NetIncomePerShareTable" xlink:label="nnbr_NetIncomePerShareTable"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_NetIncomePerShareLineItems" xlink:to="nnbr_NetIncomePerShareTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_NetIncomePerShareLineItems" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_NetIncomePerShareTable" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSegmentInformationSegmentInformation">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AutocamPrecisionComponentsGroupMember" xlink:label="nnbr_AutocamPrecisionComponentsGroupMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="us-gaap_ConsolidationItemsAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="us-gaap_ConsolidationItemsDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="us-gaap_ConsolidationItemsDomain_2"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_CorporateAndConsolidationsMember" xlink:label="nnbr_CorporateAndConsolidationsMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="us-gaap_OperatingSegmentsMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PrecisionEngineeredProductsHoldingIncMember" xlink:label="nnbr_PrecisionEngineeredProductsHoldingIncMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="us-gaap_SalesRevenueGoodsNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="us-gaap_SegmentReportingInformationLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ConsolidationItemsAxis" xlink:to="us-gaap_ConsolidationItemsDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ConsolidationItemsAxis" xlink:to="us-gaap_ConsolidationItemsDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConsolidationItemsDomain" xlink:to="us-gaap_OperatingSegmentsMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ConsolidationItemsAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_AutocamPrecisionComponentsGroupMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_PrecisionEngineeredProductsHoldingIncMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_CorporateAndConsolidationsMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_SalesRevenueGoodsNet" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_OperatingIncomeLoss" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDebtSummaryOfDebt">
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_BR" xlink:label="country_BR"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_CN" xlink:label="country_CN"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="us-gaap_DebtInstrumentCarryingAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="us-gaap_DebtInstrumentTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_FR" xlink:label="country_FR"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_IncrementalTermLoanMember" xlink:label="nnbr_IncrementalTermLoanMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCredit" xlink:label="us-gaap_LineOfCredit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LoansPayable" xlink:label="us-gaap_LoansPayable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="us-gaap_LongTermDebtCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="us-gaap_LongtermDebtTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="us-gaap_LongtermDebtTypeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NotesPayable" xlink:label="us-gaap_NotesPayable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="us-gaap_SegmentGeographicalDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="us-gaap_SegmentGeographicalDomain_2"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorNotesDueTwoThousandAndTwentyMember" xlink:label="nnbr_SeniorNotesDueTwoThousandAndTwentyMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorSecuredRevolvingFacilityMember" xlink:label="nnbr_SeniorSecuredRevolvingFacilityMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorSecuredTermLoanBMember" xlink:label="nnbr_SeniorSecuredTermLoanBMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="us-gaap_StatementGeographicalAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnamortizedDebtIssuanceExpense" xlink:label="us-gaap_UnamortizedDebtIssuanceExpense"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_SeniorSecuredTermLoanBMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_IncrementalTermLoanMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_SeniorSecuredRevolvingFacilityMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LoansPayable" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCredit" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_NotesPayable" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebt" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtCurrent" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentCarryingAmount" order="1.1300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_UnamortizedDebtIssuanceExpense" order="1.1400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtNoncurrent" order="1.1500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_StatementGeographicalAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="3.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="nnbr_SeniorNotesDueTwoThousandAndTwentyMember" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_FR" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_BR" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_CN" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain_2" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDebtSummaryOfDebtParenthetical">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="us-gaap_DebtInstrumentFaceAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="us-gaap_DebtInstrumentTable"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_IncrementalTermLoanMember" xlink:label="nnbr_IncrementalTermLoanMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_LiborPeriod" xlink:label="nnbr_LiborPeriod"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="us-gaap_LongtermDebtTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="us-gaap_LongtermDebtTypeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="us-gaap_LongtermDebtTypeDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember_2"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorNotesDueTwoThousandAndTwentyMember" xlink:label="nnbr_SeniorNotesDueTwoThousandAndTwentyMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorSecuredRevolvingFacilityMember" xlink:label="nnbr_SeniorSecuredRevolvingFacilityMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorSecuredTermLoanBMember" xlink:label="nnbr_SeniorSecuredTermLoanBMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="us-gaap_VariableRateAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="us-gaap_VariableRateDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="us-gaap_VariableRateDomain_2"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_SeniorSecuredTermLoanBMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_IncrementalTermLoanMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_SeniorSecuredRevolvingFacilityMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="nnbr_LiborPeriod" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityExpirationDate1" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_RangeAxis" order="3.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_VariableRateAxis" order="4.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="nnbr_SeniorNotesDueTwoThousandAndTwentyMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember" order="1.1300" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureDebtAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="us-gaap_DebtInstrumentFaceAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="us-gaap_DebtInstrumentMaturityDate"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentPeriodicPayment" xlink:label="us-gaap_DebtInstrumentPeriodicPayment"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsCurrentNet" xlink:label="us-gaap_DeferredFinanceCostsCurrentNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsGross" xlink:label="us-gaap_DeferredFinanceCostsGross"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExtinguishmentOfDebtAmount" xlink:label="us-gaap_ExtinguishmentOfDebtAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_IncrementalTermLoanMember" xlink:label="nnbr_IncrementalTermLoanMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_LiborPeriod" xlink:label="nnbr_LiborPeriod"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCredit" xlink:label="us-gaap_LineOfCredit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="us-gaap_LineOfCreditFacilityLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="us-gaap_LineOfCreditFacilityTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="us-gaap_LongtermDebtTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="us-gaap_LongtermDebtTypeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="us-gaap_SeniorNotesMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_SeniorSecuredRevolvingFacilityMember" xlink:label="nnbr_SeniorSecuredRevolvingFacilityMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_IncrementalTermLoanMember" order="1.1800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="nnbr_SeniorSecuredRevolvingFacilityMember" order="1.1900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_ExtinguishmentOfDebtAmount" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_PaymentsOfDebtExtinguishmentCosts" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_WriteOffOfDeferredDebtIssuanceCost" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="nnbr_LiborPeriod" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentMaturityDate" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentPeriodicPayment" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" order="1.1300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DeferredFinanceCostsGross" order="1.1400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_DeferredFinanceCostsCurrentNet" order="1.1500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCredit" order="1.1600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_LineOfCreditFacilityTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_LineOfCreditFacilityTable" xlink:to="us-gaap_CreditFacilityAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="us-gaap_SeniorNotesMember" order="1.1700" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureGoodwillNetChangesInCarryingAmountOfGoodwill">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AutocamPrecisionComponentsSegmentMember" xlink:label="nnbr_AutocamPrecisionComponentsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:label="us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="us-gaap_GoodwillLineItems"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PrecisionEngineeredProductsSegmentMember" xlink:label="nnbr_PrecisionEngineeredProductsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="us-gaap_ScheduleOfGoodwillTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_ScheduleOfGoodwillTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_Goodwill" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_GoodwillForeignCurrencyTranslationGainLoss" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfGoodwillTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_AutocamPrecisionComponentsSegmentMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_PrecisionEngineeredProductsSegmentMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureGoodwillNetAdditionalInformation">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureIntangibleAssetsNetSummaryOfChangesInCarryingAmountOfIntangibleAssetsNet">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="us-gaap_AmortizationOfIntangibleAssets"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AutocamPrecisionComponentsSegmentMember" xlink:label="nnbr_AutocamPrecisionComponentsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:label="us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PrecisionEngineeredProductsSegmentMember" xlink:label="nnbr_PrecisionEngineeredProductsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_AmortizationOfIntangibleAssets" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_AutocamPrecisionComponentsSegmentMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_PrecisionEngineeredProductsSegmentMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureIntangibleAssetsNetAdditionalInformation">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationComponentsOfShareBasedCompensationExpenseByTypeOfAward">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AllocatedShareBasedCompensationExpenseBenefit" xlink:label="nnbr_AllocatedShareBasedCompensationExpenseBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="us-gaap_PerformanceSharesMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="us-gaap_RestrictedStockUnitsRSUMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="nnbr_AllocatedShareBasedCompensationExpenseBenefit" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockUnitsRSUMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_PerformanceSharesMember" order="1.0500" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:label="us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="us-gaap_DisposalGroupClassificationAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="us-gaap_DisposalGroupClassificationDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="us-gaap_DisposalGroupClassificationDomain_2"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_ExecutiveManagementMember" xlink:label="nnbr_ExecutiveManagementMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_MonteCarloValuationModelMember" xlink:label="nnbr_MonteCarloValuationModelMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_NonExecutiveDirectorsMember" xlink:label="nnbr_NonExecutiveDirectorsMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_NumberOfMembersAwarded" xlink:label="nnbr_NumberOfMembersAwarded"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OfficerMember" xlink:label="us-gaap_OfficerMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PerformanceConditionMember" xlink:label="nnbr_PerformanceConditionMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="us-gaap_PerformanceSharesMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="us-gaap_RestrictedStockMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:label="us-gaap_TitleOfIndividualAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ValuationTechniqueAxis" xlink:label="us-gaap_ValuationTechniqueAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="us-gaap_ValuationTechniqueDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ValuationTechniqueDomain" xlink:label="us-gaap_ValuationTechniqueDomain_2"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DisposalGroupClassificationAxis" xlink:to="us-gaap_DisposalGroupClassificationDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DisposalGroupClassificationAxis" xlink:to="us-gaap_DisposalGroupClassificationDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisposalGroupClassificationDomain" xlink:to="us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" order="1.1300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_TitleOfIndividualAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_ValuationTechniqueAxis" order="3.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_DisposalGroupClassificationAxis" order="4.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="nnbr_NumberOfMembersAwarded" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_PerformanceSharesMember" order="1.1500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockMember" order="1.1700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TitleOfIndividualAxis" xlink:to="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TitleOfIndividualAxis" xlink:to="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="nnbr_NonExecutiveDirectorsMember" order="1.1400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="us-gaap_OfficerMember" order="1.1800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="nnbr_ExecutiveManagementMember" order="1.2000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ValuationTechniqueAxis" xlink:to="us-gaap_ValuationTechniqueDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ValuationTechniqueAxis" xlink:to="us-gaap_ValuationTechniqueDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ValuationTechniqueDomain" xlink:to="nnbr_PerformanceConditionMember" order="1.1600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ValuationTechniqueDomain" xlink:to="nnbr_MonteCarloValuationModelMember" order="1.1900" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationWeightedAverageAssumptionsRelevantToDeterminingTheFairValueAtTheDatesOfGrantAndStockOptionModification">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate" xlink:label="nnbr_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="nnbr_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="1.0600" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSharedBasedCompensationReconciliationOfOptionActivity">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureIncomeTaxesAdditionalInformation">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformation">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_ContingenciesAndCommitmentsLineItems" xlink:label="nnbr_ContingenciesAndCommitmentsLineItems"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_ContingenciesAndCommitmentsTable" xlink:label="nnbr_ContingenciesAndCommitmentsTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyAccrualCarryingValueCurrent" xlink:label="us-gaap_LossContingencyAccrualCarryingValueCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:label="us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_ContingenciesAndCommitmentsLineItems" xlink:to="nnbr_ContingenciesAndCommitmentsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_ContingenciesAndCommitmentsLineItems" xlink:to="us-gaap_LossContingencyEstimateOfPossibleLoss" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_ContingenciesAndCommitmentsLineItems" xlink:to="us-gaap_LossContingencyAccrualCarryingValueCurrent" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="nnbr_ContingenciesAndCommitmentsTable" xlink:to="us-gaap_RangeAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="1.0400" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureAdditionalInformation">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AutocamCorporationMember" xlink:label="nnbr_AutocamCorporationMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateJointVentureMember" xlink:label="us-gaap_CorporateJointVentureMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueFromJointVentures" xlink:label="us-gaap_DueFromJointVentures"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="dei_EntityDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="dei_EntityDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="us-gaap_EquityMethodInvesteeNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="dei_LegalEntityAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="us-gaap_SalesRevenueGoodsNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember" xlink:label="nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="dei_EntityDomain" xlink:to="nnbr_AutocamCorporationMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityMethodInvesteeNameDomain" xlink:to="nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="dei_LegalEntityAxis" xlink:to="dei_EntityDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="dei_LegalEntityAxis" xlink:to="dei_EntityDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_CorporateJointVentureMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="us-gaap_EquityMethodInvesteeNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_SalesRevenueGoodsNet" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_DueFromJointVentures" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="dei_LegalEntityAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="3.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_RangeAxis" order="4.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureSummarizedActivityRelatedToInvestmentInJointVenture">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateJointVentureMember" xlink:label="us-gaap_CorporateJointVentureMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_DividendsDeclaredAndPaidByJointVentures" xlink:label="nnbr_DividendsDeclaredAndPaidByJointVentures"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_EquityMethodInvestmentAccretionOfBasisDifferenceFromPurchaseAccounting" xlink:label="nnbr_EquityMethodInvestmentAccretionOfBasisDifferenceFromPurchaseAccounting"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_EquityMethodInvestmentForeignCurrencyTranslationGain" xlink:label="nnbr_EquityMethodInvestmentForeignCurrencyTranslationGain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="us-gaap_EquityMethodInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_CorporateJointVentureMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestments" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_IncomeLossFromEquityMethodInvestments" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="nnbr_DividendsDeclaredAndPaidByJointVentures" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="nnbr_EquityMethodInvestmentAccretionOfBasisDifferenceFromPurchaseAccounting" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="nnbr_EquityMethodInvestmentForeignCurrencyTranslationGain" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureInvestmentInJointVentureSummarizedBalanceSheetInformationOfJointVenture">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateJointVentureMember" xlink:label="us-gaap_CorporateJointVentureMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets" xlink:label="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" xlink:label="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" xlink:label="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities" xlink:label="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" xlink:label="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_CorporateJointVentureMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureFairValueMeasurementsAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_CashSettlementOfInterestRateHedges" xlink:label="nnbr_CashSettlementOfInterestRateHedges"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:label="us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeNetLiabilityPositionAggregateFairValue" xlink:label="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="us-gaap_DerivativesFairValueLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="us-gaap_LongTermDebtFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_2"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_LongTermDebtFairValue" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeGainLossOnDerivativeNet" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="nnbr_CashSettlementOfInterestRateHedges" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="1.0700" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesValuedOnRecurringBasis">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsCurrent" xlink:label="us-gaap_DerivativeAssetsCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" xlink:label="us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsNoncurrent" xlink:label="us-gaap_DerivativeAssetsNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="us-gaap_DerivativeLiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="us-gaap_DerivativeLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="us-gaap_DerivativesFairValueLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="us-gaap_FairValueInputsLevel2Member"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeAssetsCurrent" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeAssetsNoncurrent" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeLiabilitiesCurrent" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeLiabilitiesNoncurrent" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativesFairValueLineItems" xlink:to="us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel2Member" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureRestructuringAndIntegrationAdditionalInformation">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AutocamPrecisionComponentsSegmentMember" xlink:label="nnbr_AutocamPrecisionComponentsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_PrecisionEngineeredProductsSegmentMember" xlink:label="nnbr_PrecisionEngineeredProductsSegmentMember"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_RestructuringAndIntegrationCharges" xlink:label="nnbr_RestructuringAndIntegrationCharges"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="us-gaap_RestructuringCharges"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="us-gaap_RestructuringCostAndReserveLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveCurrent" xlink:label="us-gaap_RestructuringReserveCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveNoncurrent" xlink:label="us-gaap_RestructuringReserveNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_WheelingPlantMember" xlink:label="nnbr_WheelingPlantMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="nnbr_WheelingPlantMember" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="nnbr_RestructuringAndIntegrationCharges" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_RestructuringCharges" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_RestructuringReserveCurrent" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_RestructuringReserveNoncurrent" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_PrecisionEngineeredProductsSegmentMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="nnbr_AutocamPrecisionComponentsSegmentMember" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureRestructuringAndIntegrationSummaryOfRestructuringAndIntegrationCharges">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessExitCosts1" xlink:label="us-gaap_BusinessExitCosts1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="us-gaap_EmployeeSeveranceMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FacilityClosingMember" xlink:label="us-gaap_FacilityClosingMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="us-gaap_PaymentsForRestructuring"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_RestructuringAndIntegrationCharges" xlink:label="nnbr_RestructuringAndIntegrationCharges"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="us-gaap_RestructuringCharges"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="us-gaap_RestructuringCostAndReserveAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="us-gaap_RestructuringCostAndReserveLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserve" xlink:label="us-gaap_RestructuringReserve"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeveranceCosts1" xlink:label="us-gaap_SeveranceCosts1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="us-gaap_TypeOfRestructuringDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="us-gaap_TypeOfRestructuringDomain_2"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RestructuringCostAndReserveAxis" xlink:to="us-gaap_TypeOfRestructuringDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RestructuringCostAndReserveAxis" xlink:to="us-gaap_TypeOfRestructuringDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_SeveranceCosts1" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_BusinessExitCosts1" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="nnbr_RestructuringAndIntegrationCharges" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_RestructuringReserve" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_RestructuringCharges" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestructuringCostAndReserveLineItems" xlink:to="us-gaap_PaymentsForRestructuring" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:to="us-gaap_RestructuringCostAndReserveAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TypeOfRestructuringDomain" xlink:to="us-gaap_EmployeeSeveranceMember" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TypeOfRestructuringDomain" xlink:to="us-gaap_FacilityClosingMember" order="1.0900" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfOperations">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:label="nnbr_AccountingChangesAndErrorCorrectionsLineItems"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AsRevisedMember" xlink:label="nnbr_AsRevisedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="us-gaap_EarningsPerShareBasic"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="us-gaap_EarningsPerShareDiluted"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="us-gaap_RestatementAdjustmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="us-gaap_ScenarioPreviouslyReportedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:label="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="us-gaap_StatementScenarioAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_OperatingIncomeLoss" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_WriteOffOfDeferredDebtIssuanceCost" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_InterestExpense" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ProfitLoss" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_EarningsPerShareBasic" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_EarningsPerShareDiluted" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioPreviouslyReportedMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_RestatementAdjustmentMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="nnbr_AsRevisedMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedStatementsOfComprehensiveIncomeLoss">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:label="nnbr_AccountingChangesAndErrorCorrectionsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1" xlink:label="us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="us-gaap_RestatementAdjustmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="us-gaap_ScenarioPreviouslyReportedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:label="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="us-gaap_StatementScenarioAxis"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ProfitLoss" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTax" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioPreviouslyReportedMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_RestatementAdjustmentMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnCondensedConsolidatedBalanceSheets">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:label="nnbr_AccountingChangesAndErrorCorrectionsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedIncomeTaxesCurrent" xlink:label="us-gaap_AccruedIncomeTaxesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AsRevisedMember" xlink:label="nnbr_AsRevisedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="us-gaap_DeferredTaxAssetsNetCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="us-gaap_DeferredTaxLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="us-gaap_EquityMethodInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="us-gaap_OtherLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="us-gaap_RestatementAdjustmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="us-gaap_ScenarioPreviouslyReportedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:label="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="us-gaap_StatementScenarioAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_DeferredTaxAssetsNetCurrent" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AssetsCurrent" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_Goodwill" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_EquityMethodInvestments" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_Assets" order="1.0900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent" order="1.1000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AccruedIncomeTaxesCurrent" order="1.1100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_LiabilitiesCurrent" order="1.1200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_DeferredTaxLiabilitiesNoncurrent" order="1.1300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_OtherLiabilitiesNoncurrent" order="1.1400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_Liabilities" order="1.1500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock" order="1.1600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit" order="1.1700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="1.1800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="1.1900" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity" order="1.2000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioPreviouslyReportedMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_RestatementAdjustmentMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="nnbr_AsRevisedMember" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosurePriorPeriodsFinancialStatementRevisionScheduleOfRevisionOnChangesInStockholdersEquity">
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:label="nnbr_AccountingChangesAndErrorCorrectionsLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1" xlink:label="us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="us-gaap_RestatementAdjustmentMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="us-gaap_ScenarioPreviouslyReportedMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:label="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="us-gaap_StatementScenarioAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_ProfitLoss" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock" order="1.0700" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="nnbr_AccountingChangesAndErrorCorrectionsLineItems" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="1.0800" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioPreviouslyReportedMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_RestatementAdjustmentMember" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain_2" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/DisclosureSubsequentEventsAdditionalInformation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_2"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="us-gaap_BusinessAcquisitionAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:label="us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_CashSettlementOfInterestRateHedges" xlink:label="nnbr_CashSettlementOfInterestRateHedges"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_DrtMedicalLlcMember" xlink:label="nnbr_DrtMedicalLlcMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="us-gaap_SubsequentEventLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="us-gaap_SubsequentEventTable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="nnbr_DrtMedicalLlcMember" order="1.0600" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_2" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_SubsequentEventTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_BusinessCombinationAcquisitionRelatedCosts" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="nnbr_CashSettlementOfInterestRateHedges" order="1.0500" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="2.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="1.0700" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlockPolicies">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsInventoryDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsInventoryDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIntangibleAssetsDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlockTables">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTextBlock" xlink:label="us-gaap_DisclosureOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTextBlock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DisclosureOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTextBlock" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock" order="1.0300" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" order="1.0400" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_AwardTypeAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsEquityMethodInvestmentsDisclosureTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsRestructuringImpairmentAndOtherActivitiesDisclosureTextBlockTables">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:href="nnbr-20170930.xsd#nnbr_WheelingPlantMember" xlink:label="nnbr_WheelingPlantMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="nnbr_WheelingPlantMember" order="1.0100" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" order="1.0000" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="100.0000" xbrldt:closed="true" xbrldt:contextElement="segment" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock" order="1.0200" priority="2" use="optional"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" order="1.0000" priority="2" use="optional"/>
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlock">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsAccountingChangesAndErrorCorrectionsTextBlockTables">
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.nnbr.com/taxonomy/role/NotesToFinancialStatementsSubsequentEventsTextBlock">
  </definitionLink>
</linkbase>
