<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 5.5b -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: http://www.novaworks.co -->
    <!-- Field: Doc-Info; Name: Source; Value: CVLB %2D 20200930 10Q Q3 DFN.xfr; Date: 2020%2D11%2D16T21:36:57Z -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef roleURI="http://conversionlabs.com/role/DocumentAndEntityInformation" xlink:href="cvlb-20200930.xsd#DocumentAndEntityInformation" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BalanceSheets" xlink:href="cvlb-20200930.xsd#BalanceSheets" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BalanceSheetsParenthetical" xlink:href="cvlb-20200930.xsd#BalanceSheetsParenthetical" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StatementsOfOperations" xlink:href="cvlb-20200930.xsd#StatementsOfOperations" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StatementsOfChangesInStockholdersDeficit" xlink:href="cvlb-20200930.xsd#StatementsOfChangesInStockholdersDeficit" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StatementsOfCashFlows" xlink:href="cvlb-20200930.xsd#StatementsOfCashFlows" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/NatureOfOrganizationAndBusiness" xlink:href="cvlb-20200930.xsd#NatureOfOrganizationAndBusiness" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/IntangibleAssets" xlink:href="cvlb-20200930.xsd#IntangibleAssets" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/NotesPayable" xlink:href="cvlb-20200930.xsd#NotesPayable" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StockholdersEquity" xlink:href="cvlb-20200930.xsd#StockholdersEquity" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/Leases" xlink:href="cvlb-20200930.xsd#Leases" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/CommitmentsAndContingencies" xlink:href="cvlb-20200930.xsd#CommitmentsAndContingencies" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/RelatedPartyTransactions" xlink:href="cvlb-20200930.xsd#RelatedPartyTransactions" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/SubsequentEvents" xlink:href="cvlb-20200930.xsd#SubsequentEvents" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/IntangibleAssetsTables" xlink:href="cvlb-20200930.xsd#IntangibleAssetsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StockholdersEquityTables" xlink:href="cvlb-20200930.xsd#StockholdersEquityTables" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/LeasesTables" xlink:href="cvlb-20200930.xsd#LeasesTables" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/NatureOfOrganizationAndBusinessDetailsNarrative" xlink:href="cvlb-20200930.xsd#NatureOfOrganizationAndBusinessDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-ScheduleOfDisaggregatedRevenueDetails" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-ScheduleOfDisaggregatedRevenueDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-SummaryOfInventoryDetails" xlink:href="cvlb-20200930.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-SummaryOfInventoryDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/IntangibleAssetsDetailsNarrative" xlink:href="cvlb-20200930.xsd#IntangibleAssetsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/IntangibleAssets-ScheduleOfIntangibleAssetsDetails" xlink:href="cvlb-20200930.xsd#IntangibleAssets-ScheduleOfIntangibleAssetsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/NotesPayable-DetailsNarrative" xlink:href="cvlb-20200930.xsd#NotesPayable-DetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StockholdersEquityDetailsNarrative" xlink:href="cvlb-20200930.xsd#StockholdersEquityDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StockholdersEquity-ScheduleOfOptionActivityDetails" xlink:href="cvlb-20200930.xsd#StockholdersEquity-ScheduleOfOptionActivityDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/StockholdersEquity-ScheduleOfWarrantOutstandingAndExercisableDetails" xlink:href="cvlb-20200930.xsd#StockholdersEquity-ScheduleOfWarrantOutstandingAndExercisableDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/LeasesDetailsNarrative" xlink:href="cvlb-20200930.xsd#LeasesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/Leases-ScheduleOfLeasesDetails" xlink:href="cvlb-20200930.xsd#Leases-ScheduleOfLeasesDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:href="cvlb-20200930.xsd#CommitmentsAndContingenciesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/RelatedPartyTransactionsDetailsNarrative" xlink:href="cvlb-20200930.xsd#RelatedPartyTransactionsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://conversionlabs.com/role/SubsequentEventsDetailsNarrative" xlink:href="cvlb-20200930.xsd#SubsequentEventsDetailsNarrative" xlink:type="simple" />
    <link: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" />
    <link: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" />
    <link: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" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link: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" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/DocumentAndEntityInformation" xlink:title="00000001 - Document - Document And Entity Information" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BalanceSheets" xlink:title="00000002 - Statement - Condensed Consolidated Balance Sheets (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesBPreferredStockMember" xlink:label="loc_us-gaapSeriesBPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesBPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaapAssetsAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssetsAbstract_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaapAssetsCurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapAssetsCurrentAbstract_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaapAccountsReceivableNetCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapAccountsReceivableNetCurrent_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepositAssets" xlink:label="loc_us-gaapDepositAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapDepositAssets_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaapInventoryNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapInventoryNet_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaapOtherAssetsCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapOtherAssetsCurrent_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapAssetsCurrent_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsNoncurrentAbstract" xlink:label="loc_us-gaapAssetsNoncurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapAssetsNoncurrentAbstract_50" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAsset_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsNoncurrentAbstract_50" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAsset_50" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedComputerSoftwareNet" xlink:label="loc_us-gaapCapitalizedComputerSoftwareNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsNoncurrentAbstract_50" xlink:to="loc_us-gaapCapitalizedComputerSoftwareNet_50" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsNoncurrentAbstract_50" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsNet_50" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaapAssetsNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsNoncurrentAbstract_50" xlink:to="loc_us-gaapAssetsNoncurrent_50" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapAssets_50" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaapLiabilitiesCurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrent_50" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableCurrent" xlink:label="loc_us-gaapNotesPayableCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapNotesPayableCurrent_50" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaapContractWithCustomerLiabilityCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapContractWithCustomerLiabilityCurrent_50" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapLiabilitiesCurrent_50" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtNoncurrentAbstract" xlink:label="loc_us-gaapLongTermDebtNoncurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaapOperatingLeaseLiability_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:to="loc_us-gaapOperatingLeaseLiability_50" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ContingentConsiderationOnPurchaseOfLegalsimpli" xlink:label="loc_CVLBContingentConsiderationOnPurchaseOfLegalsimpli_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:to="loc_CVLBContingentConsiderationOnPurchaseOfLegalsimpli_50" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaapOtherLiabilitiesNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:to="loc_us-gaapOtherLiabilitiesNoncurrent_50" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SeriesBPreferredStockPutLiability" xlink:label="loc_CVLBSeriesBPreferredStockPutLiability_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:to="loc_CVLBSeriesBPreferredStockPutLiability_50" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaapDeferredIncomeTaxLiabilitiesNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongTermDebtNoncurrentAbstract_50" xlink:to="loc_us-gaapDeferredIncomeTaxLiabilitiesNet_50" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLiabilities_50" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaapCommitmentsAndContingencies_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapCommitmentsAndContingencies_50" xlink:type="arc" order="28" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaapStockholdersEquityAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapStockholdersEquityAbstract_50" xlink:type="arc" order="29" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapPreferredStockValue_50" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapCommonStockValue_50" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaapAdditionalPaidInCapital_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapAdditionalPaidInCapital_50" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" xlink:type="arc" order="33" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_EquityTotal" xlink:label="loc_CVLBEquityTotal_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_CVLBEquityTotal_50" xlink:type="arc" order="34" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaapTreasuryStockValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapTreasuryStockValue_50" xlink:type="arc" order="35" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapStockholdersEquity_50" xlink:type="arc" order="36" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaapMinorityInterest_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapMinorityInterest_50" xlink:type="arc" order="37" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_50" xlink:type="arc" order="38" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquity_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLiabilitiesAndStockholdersEquity_50" xlink:type="arc" order="39" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BalanceSheetsParenthetical" xlink:title="00000003 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesBPreferredStockMember" xlink:label="loc_us-gaapSeriesBPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesBPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaapPreferredStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesIssued_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockCommonShares" xlink:label="loc_us-gaapTreasuryStockCommonShares_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapTreasuryStockCommonShares_50" xlink:type="arc" order="8" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StatementsOfOperations" xlink:title="00000004 - Statement - Condensed Consolidated Statements of Operations (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProductRevenuesNetMember" xlink:label="loc_CVLBProductRevenuesNetMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBProductRevenuesNetMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SoftwareRevenuesNetMember" xlink:label="loc_CVLBSoftwareRevenuesNetMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBSoftwareRevenuesNetMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ServiceRevenuesNetMember" xlink:label="loc_CVLBServiceRevenuesNetMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBServiceRevenuesNetMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_170" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaapCostOfRevenue_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCostOfRevenue_170" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaapGrossProfit_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapGrossProfit_170" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaapOperatingExpensesAbstract_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOperatingExpensesAbstract_170" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaapSellingAndMarketingExpense_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_us-gaapSellingAndMarketingExpense_170" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaapGeneralAndAdministrativeExpense_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_us-gaapGeneralAndAdministrativeExpense_170" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherGeneralExpense" xlink:label="loc_us-gaapOtherGeneralExpense_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_us-gaapOtherGeneralExpense_170" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CustomerServiceExpenses" xlink:label="loc_CVLBCustomerServiceExpenses_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_CVLBCustomerServiceExpenses_170" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DevelopmentCosts" xlink:label="loc_us-gaapDevelopmentCosts_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_us-gaapDevelopmentCosts_170" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaapOperatingExpenses_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapOperatingExpensesAbstract_170" xlink:to="loc_us-gaapOperatingExpenses_170" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaapOperatingIncomeLoss_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOperatingIncomeLoss_170" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaapInterestExpense_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapInterestExpense_170" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_170" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaapIncomeTaxExpenseBenefit_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncomeTaxExpenseBenefit_170" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaapProfitLoss_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProfitLoss_170" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaapNetIncomeLossAttributableToNoncontrollingInterest_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLossAttributableToNoncontrollingInterest_170" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss_170" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DeemedDistributionToHoldersOfCommonAndSeriesBPreferredStock" xlink:label="loc_CVLBDeemedDistributionToHoldersOfCommonAndSeriesBPreferredStock_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDeemedDistributionToHoldersOfCommonAndSeriesBPreferredStock_170" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="loc_us-gaapNetIncomeLossAvailableToCommonStockholdersBasic_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLossAvailableToCommonStockholdersBasic_170" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsPerBasicShare_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsPerBasicShare_170" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsPerDilutedShare_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsPerDilutedShare_170" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaapEarningsPerShareAbstract_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapEarningsPerShareAbstract_170" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaapWeightedAverageNumberOfSharesOutstandingBasic_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEarningsPerShareAbstract_170" xlink:to="loc_us-gaapWeightedAverageNumberOfSharesOutstandingBasic_170" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaapWeightedAverageNumberOfDilutedSharesOutstanding_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEarningsPerShareAbstract_170" xlink:to="loc_us-gaapWeightedAverageNumberOfDilutedSharesOutstanding_170" xlink:type="arc" order="23" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StatementsOfChangesInStockholdersDeficit" xlink:title="00000005 - Statement - Condensed Consolidated Statements of Changes in Stockholders&apos; Deficit (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaapTreasuryStockMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapTreasuryStockMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ParentMember" xlink:label="loc_us-gaapParentMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapParentMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaapNoncontrollingInterestMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapNoncontrollingInterestMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_80" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaapSharesOutstanding_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesOutstanding_80" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_80" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_80" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueShareBasedCompensation_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueShareBasedCompensation_80" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_80" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DistributionsToNoncontrollingInterest" xlink:label="loc_CVLBDistributionsToNoncontrollingInterest_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDistributionsToNoncontrollingInterest_80" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AgreementToIssueSharesForNoncontrollingInterest" xlink:label="loc_CVLBAgreementToIssueSharesForNoncontrollingInterest_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAgreementToIssueSharesForNoncontrollingInterest_80" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AgreementToIssueSharesForNoncontrollingInterestShares" xlink:label="loc_CVLBAgreementToIssueSharesForNoncontrollingInterestShares_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAgreementToIssueSharesForNoncontrollingInterestShares_80" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:label="loc_us-gaapAdjustmentsToAdditionalPaidInCapitalWarrantIssued_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAdjustmentsToAdditionalPaidInCapitalWarrantIssued_80" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodValueExerciseOfWarrants" xlink:label="loc_CVLBStockIssuedDuringPeriodValueExerciseOfWarrants_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodValueExerciseOfWarrants_80" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodSharesExerciseOfWarrants" xlink:label="loc_CVLBStockIssuedDuringPeriodSharesExerciseOfWarrants_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodSharesExerciseOfWarrants_80" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CashlessExerciseOfWarrants" xlink:label="loc_CVLBCashlessExerciseOfWarrants_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCashlessExerciseOfWarrants_80" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CashlessExerciseOfWarrantsShares" xlink:label="loc_CVLBCashlessExerciseOfWarrantsShares_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCashlessExerciseOfWarrantsShares_80" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueStockOptionsExercised_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueStockOptionsExercised_80" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_80" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodValueCashlessExerciseOfStockOptions" xlink:label="loc_CVLBStockIssuedDuringPeriodValueCashlessExerciseOfStockOptions_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodValueCashlessExerciseOfStockOptions_80" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodSharesCashlessExerciseOfStockOptions" xlink:label="loc_CVLBStockIssuedDuringPeriodSharesCashlessExerciseOfStockOptions_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodSharesCashlessExerciseOfStockOptions_80" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AdjustmentsToAdditionalPaidInCapitalDeemedDividendFromWarrantsIssuedAndBcfWithSeriesBPreferredStock" xlink:label="loc_CVLBAdjustmentsToAdditionalPaidInCapitalDeemedDividendFromWarrantsIssuedAndBcfWithSeriesBPreferredStock_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAdjustmentsToAdditionalPaidInCapitalDeemedDividendFromWarrantsIssuedAndBcfWithSeriesBPreferredStock_80" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DeemedDividendFromDownroundProvisionInCommonStockSharesYetToBeIssued" xlink:label="loc_CVLBDeemedDividendFromDownroundProvisionInCommonStockSharesYetToBeIssued_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDeemedDividendFromDownroundProvisionInCommonStockSharesYetToBeIssued_80" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DeemedDividendFromWarrantPriceAdjustments" xlink:label="loc_CVLBDeemedDividendFromWarrantPriceAdjustments_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDeemedDividendFromWarrantPriceAdjustments_80" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithStock" xlink:label="loc_CVLBAdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithStock_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithStock_80" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithDebt" xlink:label="loc_CVLBAdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithDebt_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAdjustmentsToAdditionalPaidInCapitalWarrantsIssuedInConjunctionWithDebt_80" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_80" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_80" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodValueSaleOfCommonStock" xlink:label="loc_CVLBStockIssuedDuringPeriodValueSaleOfCommonStock_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodValueSaleOfCommonStock_80" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodSharesSaleOfCommonStock" xlink:label="loc_CVLBStockIssuedDuringPeriodSharesSaleOfCommonStock_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodSharesSaleOfCommonStock_80" xlink:type="arc" order="28" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueOther" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueOther_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueOther_80" xlink:type="arc" order="29" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesOther_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesOther_80" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaapProfitLoss_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProfitLoss_80" xlink:type="arc" order="31" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StatementsOfCashFlows" xlink:title="00000006 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/NatureOfOrganizationAndBusiness" xlink:title="00000007 - Disclosure - Nature of the Organization and Business" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies" xlink:title="00000008 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/IntangibleAssets" xlink:title="00000009 - Disclosure - Intangible Assets" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/NotesPayable" xlink:title="00000010 - Disclosure - Notes Payable" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StockholdersEquity" xlink:title="00000011 - Disclosure - Stockholders&apos; Equity" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/Leases" xlink:title="00000012 - Disclosure - Leases" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/CommitmentsAndContingencies" xlink:title="00000013 - Disclosure - Commitments and Contingencies" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/RelatedPartyTransactions" xlink:title="00000014 - Disclosure - Related Party Transactions" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/SubsequentEvents" xlink:title="00000015 - Disclosure - Subsequent Events" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:title="00000016 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:title="00000017 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/IntangibleAssetsTables" xlink:title="00000018 - Disclosure - Intangible Assets (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StockholdersEquityTables" xlink:title="00000019 - Disclosure - Stockholders&apos; Equity (Tables)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ServiceBasedStockOptionsMember" xlink:label="loc_CVLBServiceBasedStockOptionsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBServiceBasedStockOptionsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaapPerformanceSharesMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaapPerformanceSharesMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="loc_us-gaapScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock" xlink:label="loc_us-gaapScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock_40" xlink:type="arc" order="1" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/LeasesTables" xlink:title="00000020 - Disclosure - Leases (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/NatureOfOrganizationAndBusinessDetailsNarrative" xlink:title="00000021 - Disclosure - Nature of the Organization and Business (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ImmudynePrLlcMember" xlink:label="loc_CVLBImmudynePrLlcMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_CVLBImmudynePrLlcMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LegalSimpliSoftwareLlcMember" xlink:label="loc_CVLBLegalSimpliSoftwareLlcMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_CVLBLegalSimpliSoftwareLlcMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProductRevenuesNetMember" xlink:label="loc_CVLBProductRevenuesNetMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBProductRevenuesNetMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SoftwareRevenuesNetMember" xlink:label="loc_CVLBSoftwareRevenuesNetMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBSoftwareRevenuesNetMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srtStatementScenarioAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtStatementScenarioAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SinceInceptionMember" xlink:label="loc_CVLBSinceInceptionMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtScenarioUnspecifiedDomain" xlink:to="loc_CVLBSinceInceptionMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaapSubsequentEventTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapSubsequentEventTypeAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaapSubsequentEventMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSubsequentEventTypeDomain" xlink:to="loc_us-gaapSubsequentEventMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateAxis" xlink:label="loc_us-gaapAwardDateAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardDateAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateDomain" xlink:label="loc_us-gaapAwardDateDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardDateAxis" xlink:to="loc_us-gaapAwardDateDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateDomain" xlink:label="loc_us-gaapAwardDateDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardDateAxis" xlink:to="loc_us-gaapAwardDateDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ThroughTheNextTwelveMonthsMember" xlink:label="loc_CVLBThroughTheNextTwelveMonthsMember_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAwardDateDomain" xlink:to="loc_CVLBThroughTheNextTwelveMonthsMember_80" xlink:type="arc" order="81" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_100" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_100" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_100" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaapBusinessAcquisitionPercentageOfVotingInterestsAcquired_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapBusinessAcquisitionPercentageOfVotingInterestsAcquired_100" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="loc_us-gaapStockholdersEquityReverseStockSplit_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquityReverseStockSplit_100" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement_100" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AdditionalCash" xlink:label="loc_CVLBAdditionalCash_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBAdditionalCash_100" xlink:type="arc" order="6" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:title="00000022 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LegalSimpliSoftwareLlcMember" xlink:label="loc_CVLBLegalSimpliSoftwareLlcMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_CVLBLegalSimpliSoftwareLlcMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProductRevenuesNetMember" xlink:label="loc_CVLBProductRevenuesNetMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBProductRevenuesNetMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_110" xlink:type="arc" order="111" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srtStatementScenarioAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtStatementScenarioAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CapitalizedStockBasedCompensationMember" xlink:label="loc_CVLBCapitalizedStockBasedCompensationMember_130" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtScenarioUnspecifiedDomain" xlink:to="loc_CVLBCapitalizedStockBasedCompensationMember_130" xlink:type="arc" order="131" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaapAntidilutiveSecuritiesNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaapAntidilutiveSecuritiesNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="loc_us-gaapAntidilutiveSecuritiesNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OptionsAndWarrantsMember" xlink:label="loc_CVLBOptionsAndWarrantsMember_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:to="loc_CVLBOptionsAndWarrantsMember_140" xlink:type="arc" order="141" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srtMajorCustomersAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtMajorCustomersAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srtNameOfMajorCustomerDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtMajorCustomersAxis" xlink:to="loc_srtNameOfMajorCustomerDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srtNameOfMajorCustomerDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtMajorCustomersAxis" xlink:to="loc_srtNameOfMajorCustomerDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoManufacturersMember" xlink:label="loc_CVLBTwoManufacturersMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtNameOfMajorCustomerDomain" xlink:to="loc_CVLBTwoManufacturersMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_MinorityInterestRate" xlink:label="loc_CVLBMinorityInterestRate_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBMinorityInterestRate_180" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CustomerDiscountsReturnsAndRebates" xlink:label="loc_CVLBCustomerDiscountsReturnsAndRebates_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCustomerDiscountsReturnsAndRebates_180" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SubscriptionPricePerShare" xlink:label="loc_CVLBSubscriptionPricePerShare_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBSubscriptionPricePerShare_180" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaapContractWithCustomerLiabilityCurrent_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapContractWithCustomerLiabilityCurrent_180" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaapProvisionForDoubtfulAccounts_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProvisionForDoubtfulAccounts_180" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaapAccountsReceivableNet_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccountsReceivableNet_180" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="loc_us-gaapAllowanceForDoubtfulAccountsReceivableCurrent_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAllowanceForDoubtfulAccountsReceivableCurrent_180" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryLIFOReserve" xlink:label="loc_us-gaapInventoryLIFOReserve_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapInventoryLIFOReserve_180" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DepositsPercentage" xlink:label="loc_CVLBDepositsPercentage_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDepositsPercentage_180" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepositAssets" xlink:label="loc_us-gaapDepositAssets_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDepositAssets_180" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurchaseCommitments" xlink:label="loc_CVLBPurchaseCommitments_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPurchaseCommitments_180" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedSoftwareDevelopmentCostsForSoftwareSoldToCustomers" xlink:label="loc_us-gaapCapitalizedSoftwareDevelopmentCostsForSoftwareSoldToCustomers_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCapitalizedSoftwareDevelopmentCostsForSoftwareSoldToCustomers_180" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:label="loc_us-gaapCapitalizedComputerSoftwareAmortization1_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCapitalizedComputerSoftwareAmortization1_180" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LiabilityToIssuanceOfCommonStock" xlink:label="loc_CVLBLiabilityToIssuanceOfCommonStock_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBLiabilityToIssuanceOfCommonStock_180" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CommonStockFairValue" xlink:label="loc_CVLBCommonStockFairValue_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCommonStockFairValue_180" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProceedsFromCashReceiptsFromInvestorsForUnissuedShares" xlink:label="loc_CVLBProceedsFromCashReceiptsFromInvestorsForUnissuedShares_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBProceedsFromCashReceiptsFromInvestorsForUnissuedShares_180" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_180" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaapConcentrationRiskPercentage1_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapConcentrationRiskPercentage1_180" xlink:type="arc" order="17" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-ScheduleOfDisaggregatedRevenueDetails" xlink:title="00000023 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Disaggregated Revenue (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProductRevenuesNetMember" xlink:label="loc_CVLBProductRevenuesNetMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBProductRevenuesNetMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SoftwareRevenueMember" xlink:label="loc_CVLBSoftwareRevenueMember_280" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_CVLBSoftwareRevenueMember_280" xlink:type="arc" order="281" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaapStatementBusinessSegmentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementBusinessSegmentsAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaapSegmentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementBusinessSegmentsAxis" xlink:to="loc_us-gaapSegmentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaapSegmentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementBusinessSegmentsAxis" xlink:to="loc_us-gaapSegmentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShapiroMDMember" xlink:label="loc_CVLBShapiroMDMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBShapiroMDMember_0" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_RexMDMember" xlink:label="loc_CVLBRexMDMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBRexMDMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_INRWellnessMember" xlink:label="loc_CVLBINRWellnessMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBINRWellnessMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurpurexMember" xlink:label="loc_CVLBPurpurexMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBPurpurexMember_30" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ScarologyMember" xlink:label="loc_CVLBScarologyMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBScarologyMember_40" xlink:type="arc" order="42" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OtherMiscServiceMember" xlink:label="loc_CVLBOtherMiscServiceMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBOtherMiscServiceMember_50" xlink:type="arc" order="52" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LegalSimpliMember" xlink:label="loc_CVLBLegalSimpliMember_280" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSegmentDomain" xlink:to="loc_CVLBLegalSimpliMember_280" xlink:type="arc" order="282" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CVLBPRMember" xlink:label="loc_CVLBCVLBPRMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_CVLBCVLBPRMember_0" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax_370" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPolicies-SummaryOfInventoryDetails" xlink:title="00000024 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Summary of Inventory (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/IntangibleAssetsDetailsNarrative" xlink:title="00000025 - Disclosure - Intangible Assets (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/IntangibleAssets-ScheduleOfIntangibleAssetsDetails" xlink:title="00000026 - Disclosure - Intangible Assets - Schedule of Intangible Assets (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CustomerRelationshipAssetMember" xlink:label="loc_CVLBCustomerRelationshipAssetMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_CVLBCustomerRelationshipAssetMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurchasedLicensesMember" xlink:label="loc_CVLBPurchasedLicensesMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_CVLBPurchasedLicensesMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetUsefulLife_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetUsefulLife_80" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsGross_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsGross_80" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization_80" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsNet_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsNet_80" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/NotesPayable-DetailsNarrative" xlink:title="00000027 - Disclosure - Notes Payable - (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SecuritiesPurchaseAgreementMember" xlink:label="loc_CVLBSecuritiesPurchaseAgreementMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBSecuritiesPurchaseAgreementMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_NoteRepaymentAndWarrantAmendmentAgreementMember" xlink:label="loc_CVLBNoteRepaymentAndWarrantAmendmentAgreementMember_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBNoteRepaymentAndWarrantAmendmentAgreementMember_90" xlink:type="arc" order="91" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixPurchaseAgreementsMember" xlink:label="loc_CVLBCSixPurchaseAgreementsMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBCSixPurchaseAgreementsMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixPurchaseAgreementOneMember" xlink:label="loc_CVLBCSixPurchaseAgreementOneMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBCSixPurchaseAgreementOneMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixPurchaseAgreementTwoMember" xlink:label="loc_CVLBCSixPurchaseAgreementTwoMember_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBCSixPurchaseAgreementTwoMember_160" xlink:type="arc" order="161" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixPurchaseAgreementsOneMember" xlink:label="loc_CVLBCSixPurchaseAgreementsOneMember_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBCSixPurchaseAgreementsOneMember_170" xlink:type="arc" order="171" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixPurchaseAgreementsTwoMember" xlink:label="loc_CVLBCSixPurchaseAgreementsTwoMember_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBCSixPurchaseAgreementsTwoMember_180" xlink:type="arc" order="181" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoCSixPurchaseAgreementsMember" xlink:label="loc_CVLBTwoCSixPurchaseAgreementsMember_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBTwoCSixPurchaseAgreementsMember_200" xlink:type="arc" order="201" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PaycheckProtectionProgramLoanMember" xlink:label="loc_CVLBPaycheckProtectionProgramLoanMember_240" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBPaycheckProtectionProgramLoanMember_240" xlink:type="arc" order="241" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AlphaCapitalAnstaltBrioCapitalMasterFundLtdMember" xlink:label="loc_CVLBAlphaCapitalAnstaltBrioCapitalMasterFundLtdMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBAlphaCapitalAnstaltBrioCapitalMasterFundLtdMember_0" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CSixCapitalLLCMember" xlink:label="loc_CVLBCSixCapitalLLCMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBCSixCapitalLLCMember_120" xlink:type="arc" order="122" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ThreeAccreditedInvestorsMember" xlink:label="loc_CVLBThreeAccreditedInvestorsMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBThreeAccreditedInvestorsMember_50" xlink:type="arc" order="52" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SixAccreditedInvestorsMember" xlink:label="loc_CVLBSixAccreditedInvestorsMember_210" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBSixAccreditedInvestorsMember_210" xlink:type="arc" order="212" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_USSmallBusinessAdministrationMember" xlink:label="loc_CVLBUSSmallBusinessAdministrationMember_240" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBUSSmallBusinessAdministrationMember_240" xlink:type="arc" order="242" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_60" xlink:type="arc" order="63" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_70" xlink:type="arc" order="73" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srtStatementScenarioAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtStatementScenarioAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PreSplitBasisMember" xlink:label="loc_CVLBPreSplitBasisMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtScenarioUnspecifiedDomain" xlink:to="loc_CVLBPreSplitBasisMember_10" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PerAgreementMember" xlink:label="loc_CVLBPerAgreementMember_130" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtScenarioUnspecifiedDomain" xlink:to="loc_CVLBPerAgreementMember_130" xlink:type="arc" order="133" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DailyAveragePaymentMember" xlink:label="loc_CVLBDailyAveragePaymentMember_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBDailyAveragePaymentMember_190" xlink:type="arc" order="193" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_MayTwoThousandAndTwentyNotesMember" xlink:label="loc_CVLBMayTwoThousandAndTwentyNotesMember_210" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_CVLBMayTwoThousandAndTwentyNotesMember_210" xlink:type="arc" order="211" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaapDebtInstrumentFaceAmount_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentFaceAmount_340" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:label="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_340" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaapDebtInstrumentInterestRateStatedPercentage_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateStatedPercentage_340" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentRate" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentRate_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentRate_340" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaapDebtInstrumentConvertibleConversionPrice1_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentConvertibleConversionPrice1_340" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentAmount1_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentAmount1_340" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DebtConversionInterestValue" xlink:label="loc_CVLBDebtConversionInterestValue_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDebtConversionInterestValue_340" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayable" xlink:label="loc_us-gaapNotesPayable_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNotesPayable_340" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="loc_us-gaapDebtInstrumentMaturityDate_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentMaturityDate_340" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfNotesPayable" xlink:label="loc_us-gaapRepaymentsOfNotesPayable_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRepaymentsOfNotesPayable_340" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_340" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="loc_us-gaapClassOfWarrantOrRightOutstanding_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightOutstanding_340" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OriginalIssueDiscountPercentage" xlink:label="loc_CVLBOriginalIssueDiscountPercentage_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBOriginalIssueDiscountPercentage_340" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaapDebtInstrumentUnamortizedDiscount_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentUnamortizedDiscount_340" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaapDeferredFinanceCostsNet_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDeferredFinanceCostsNet_340" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromNotesPayable" xlink:label="loc_us-gaapProceedsFromNotesPayable_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromNotesPayable_340" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConvertibleNotesPayable" xlink:label="loc_us-gaapConvertibleNotesPayable_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapConvertibleNotesPayable_340" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConvertibleNotesPayableCurrent" xlink:label="loc_us-gaapConvertibleNotesPayableCurrent_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapConvertibleNotesPayableCurrent_340" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet" xlink:label="loc_us-gaapDebtInstrumentUnamortizedDiscountPremiumNet_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentUnamortizedDiscountPremiumNet_340" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="loc_us-gaapProceedsFromConvertibleDebt_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromConvertibleDebt_340" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="loc_us-gaapInterestPayableCurrentAndNoncurrent_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapInterestPayableCurrentAndNoncurrent_340" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="loc_us-gaapInterestExpenseDebt_340" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapInterestExpenseDebt_340" xlink:type="arc" order="21" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StockholdersEquityDetailsNarrative" xlink:title="00000028 - Disclosure - Stockholders&apos; Equity (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaapPreferredStockMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapPreferredStockMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesBPreferredStockMember" xlink:label="loc_us-gaapSeriesBPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesBPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SeriesBConvertiblePreferredStockMember" xlink:label="loc_CVLBSeriesBConvertiblePreferredStockMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_CVLBSeriesBConvertiblePreferredStockMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ClassAWarrantMember" xlink:label="loc_CVLBClassAWarrantMember_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_CVLBClassAWarrantMember_160" xlink:type="arc" order="162" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_50" xlink:type="arc" order="52" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_360" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_360" xlink:type="arc" order="364" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SecuritiesPurchaseAgreementMember" xlink:label="loc_CVLBSecuritiesPurchaseAgreementMember_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBSecuritiesPurchaseAgreementMember_80" xlink:type="arc" order="81" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ConsultingAgreementMember" xlink:label="loc_CVLBConsultingAgreementMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBConsultingAgreementMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantPurchaseAgreementMember" xlink:label="loc_CVLBWarrantPurchaseAgreementMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBWarrantPurchaseAgreementMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurchaseAgreementMember" xlink:label="loc_CVLBPurchaseAgreementMember_330" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBPurchaseAgreementMember_330" xlink:type="arc" order="332" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ServicesAgreementMember" xlink:label="loc_CVLBServicesAgreementMember_350" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBServicesAgreementMember_350" xlink:type="arc" order="352" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_NoteRepaymentAndWarrantAmendmentAgreementMember" xlink:label="loc_CVLBNoteRepaymentAndWarrantAmendmentAgreementMember_450" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBNoteRepaymentAndWarrantAmendmentAgreementMember_450" xlink:type="arc" order="451" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndEighteenAlphaAmendmentMember" xlink:label="loc_CVLBTwoThousandAndEighteenAlphaAmendmentMember_460" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBTwoThousandAndEighteenAlphaAmendmentMember_460" xlink:type="arc" order="461" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndNineteenAlphaAmendmentMember" xlink:label="loc_CVLBTwoThousandAndNineteenAlphaAmendmentMember_480" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBTwoThousandAndNineteenAlphaAmendmentMember_480" xlink:type="arc" order="481" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SecondAlphaWarrantAmendmentMember" xlink:label="loc_CVLBSecondAlphaWarrantAmendmentMember_500" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBSecondAlphaWarrantAmendmentMember_500" xlink:type="arc" order="501" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndEighteenBrioWarrantAmendmentMember" xlink:label="loc_CVLBTwoThousandAndEighteenBrioWarrantAmendmentMember_550" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBTwoThousandAndEighteenBrioWarrantAmendmentMember_550" xlink:type="arc" order="551" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AmendedConsultingAgreementMember" xlink:label="loc_CVLBAmendedConsultingAgreementMember_650" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBAmendedConsultingAgreementMember_650" xlink:type="arc" order="651" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaapWarrantMember_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapWarrantMember_140" xlink:type="arc" order="142" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_270" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_270" xlink:type="arc" order="271" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockOptionsMember" xlink:label="loc_CVLBStockOptionsMember_290" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBStockOptionsMember_290" xlink:type="arc" order="291" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantOneMember" xlink:label="loc_CVLBWarrantOneMember_300" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBWarrantOneMember_300" xlink:type="arc" order="301" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BrioWarrantsMember" xlink:label="loc_CVLBBrioWarrantsMember_630" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBBrioWarrantsMember_630" xlink:type="arc" order="631" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeAxis" xlink:label="loc_us-gaapMeasurementInputTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapMeasurementInputTypeAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="loc_us-gaapMeasurementInputTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapMeasurementInputTypeAxis" xlink:to="loc_us-gaapMeasurementInputTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="loc_us-gaapMeasurementInputTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapMeasurementInputTypeAxis" xlink:to="loc_us-gaapMeasurementInputTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputExpectedDividendRateMember" xlink:label="loc_us-gaapMeasurementInputExpectedDividendRateMember_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapMeasurementInputTypeDomain" xlink:to="loc_us-gaapMeasurementInputExpectedDividendRateMember_190" xlink:type="arc" order="191" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputPriceVolatilityMember" xlink:label="loc_us-gaapMeasurementInputPriceVolatilityMember_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapMeasurementInputTypeDomain" xlink:to="loc_us-gaapMeasurementInputPriceVolatilityMember_200" xlink:type="arc" order="201" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember" xlink:label="loc_us-gaapMeasurementInputRiskFreeInterestRateMember_210" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapMeasurementInputTypeDomain" xlink:to="loc_us-gaapMeasurementInputRiskFreeInterestRateMember_210" xlink:type="arc" order="211" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AlphaAndBrioMember" xlink:label="loc_CVLBAlphaAndBrioMember_240" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBAlphaAndBrioMember_240" xlink:type="arc" order="241" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestorMember" xlink:label="loc_us-gaapInvestorMember_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_us-gaapInvestorMember_260" xlink:type="arc" order="261" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ChiefExecutiveOfficerAndChiefTechnologyOfficerMember" xlink:label="loc_CVLBChiefExecutiveOfficerAndChiefTechnologyOfficerMember_330" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBChiefExecutiveOfficerAndChiefTechnologyOfficerMember_330" xlink:type="arc" order="331" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_MrSeanFitzpatrickMember" xlink:label="loc_CVLBMrSeanFitzpatrickMember_350" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBMrSeanFitzpatrickMember_350" xlink:type="arc" order="351" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ThreeEmployeesTwoAdvisoryBoardMembersAndOneVendorMember" xlink:label="loc_CVLBThreeEmployeesTwoAdvisoryBoardMembersAndOneVendorMember_380" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBThreeEmployeesTwoAdvisoryBoardMembersAndOneVendorMember_380" xlink:type="arc" order="381" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srtStatementScenarioAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtStatementScenarioAxis" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PreSplitBasisMember" xlink:label="loc_CVLBPreSplitBasisMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtScenarioUnspecifiedDomain" xlink:to="loc_CVLBPreSplitBasisMember_60" xlink:type="arc" order="63" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ServiceBasedStockOptionsMember" xlink:label="loc_CVLBServiceBasedStockOptionsMember_350" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBServiceBasedStockOptionsMember_350" xlink:type="arc" order="353" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AugustTwoThousandAndTwentyWarrantInducementMember" xlink:label="loc_CVLBAugustTwoThousandAndTwentyWarrantInducementMember_400" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBAugustTwoThousandAndTwentyWarrantInducementMember_400" xlink:type="arc" order="401" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AlphaCapitalAnstaltMember" xlink:label="loc_CVLBAlphaCapitalAnstaltMember_450" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBAlphaCapitalAnstaltMember_450" xlink:type="arc" order="452" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BrioMasterFundMember" xlink:label="loc_CVLBBrioMasterFundMember_550" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBBrioMasterFundMember_550" xlink:type="arc" order="552" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BlueHorizonConsultingLLCMember" xlink:label="loc_CVLBBlueHorizonConsultingLLCMember_650" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBBlueHorizonConsultingLLCMember_650" xlink:type="arc" order="652" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaapPlanNameAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapPlanNameAxis" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaapPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPlanNameAxis" xlink:to="loc_us-gaapPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaapPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPlanNameAxis" xlink:to="loc_us-gaapPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndEighteenAlphaNoteMember" xlink:label="loc_CVLBTwoThousandAndEighteenAlphaNoteMember_450" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBTwoThousandAndEighteenAlphaNoteMember_450" xlink:type="arc" order="453" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndEighteenAlphaWarrantMember" xlink:label="loc_CVLBTwoThousandAndEighteenAlphaWarrantMember_460" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBTwoThousandAndEighteenAlphaWarrantMember_460" xlink:type="arc" order="463" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndNineteenAlphaWarrantMember" xlink:label="loc_CVLBTwoThousandAndNineteenAlphaWarrantMember_480" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBTwoThousandAndNineteenAlphaWarrantMember_480" xlink:type="arc" order="483" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_AugustTwoThousandAndNineteenWarrantMember" xlink:label="loc_CVLBAugustTwoThousandAndNineteenWarrantMember_500" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBAugustTwoThousandAndNineteenWarrantMember_500" xlink:type="arc" order="502" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TwoThousandAndEighteenBrioWarrantMember" xlink:label="loc_CVLBTwoThousandAndEighteenBrioWarrantMember_550" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBTwoThousandAndEighteenBrioWarrantMember_550" xlink:type="arc" order="553" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BrioTwoThousandAndNineteenWarrantMember" xlink:label="loc_CVLBBrioTwoThousandAndNineteenWarrantMember_570" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_CVLBBrioTwoThousandAndNineteenWarrantMember_570" xlink:type="arc" order="573" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_680" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_680" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_680" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaapPreferredStockParOrStatedValuePerShare_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockParOrStatedValuePerShare_680" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesIssuedPricePerShare" xlink:label="loc_us-gaapSharesIssuedPricePerShare_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesIssuedPricePerShare_680" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SharesIssuedPricePerSharePreSplit" xlink:label="loc_CVLBSharesIssuedPricePerSharePreSplit_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBSharesIssuedPricePerSharePreSplit_680" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage" xlink:label="loc_us-gaapPreferredStockDividendRatePercentage_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockDividendRatePercentage_680" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_680" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_680" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_680" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity" xlink:label="loc_us-gaapProceedsFromIssuanceOrSaleOfEquity_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOrSaleOfEquity_680" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentAmount1_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentAmount1_680" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockDividendsAndOtherAdjustments" xlink:label="loc_us-gaapPreferredStockDividendsAndOtherAdjustments_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockDividendsAndOtherAdjustments_680" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PutLiability" xlink:label="loc_CVLBPutLiability_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPutLiability_680" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PutLiabilityIncrease" xlink:label="loc_CVLBPutLiabilityIncrease_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPutLiabilityIncrease_680" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockValue_680" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_680" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantPurchasePrice" xlink:label="loc_CVLBWarrantPurchasePrice_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBWarrantPurchasePrice_680" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="loc_us-gaapWarrantsAndRightsOutstanding_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapWarrantsAndRightsOutstanding_680" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantsAndRightsOutstandingMeasurementInput" xlink:label="loc_us-gaapWarrantsAndRightsOutstandingMeasurementInput_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapWarrantsAndRightsOutstandingMeasurementInput_680" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantsAndRightsOutstandingTerm" xlink:label="loc_us-gaapWarrantsAndRightsOutstandingTerm_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapWarrantsAndRightsOutstandingTerm_680" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="loc_us-gaapAmortizationOfFinancingCosts_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAmortizationOfFinancingCosts_680" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_UnamortizedCosts" xlink:label="loc_CVLBUnamortizedCosts_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBUnamortizedCosts_680" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CashlessExerciseOfWarrantsShares" xlink:label="loc_CVLBCashlessExerciseOfWarrantsShares_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCashlessExerciseOfWarrantsShares_680" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_680" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_680" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_StockIssuedDuringPeriodSharesIssuedForShareLiability" xlink:label="loc_CVLBStockIssuedDuringPeriodSharesIssuedForShareLiability_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBStockIssuedDuringPeriodSharesIssuedForShareLiability_680" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfWarrants" xlink:label="loc_us-gaapProceedsFromIssuanceOfWarrants_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOfWarrants_680" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_NumberOfSharesIssuedForExerciseOfWarrants" xlink:label="loc_CVLBNumberOfSharesIssuedForExerciseOfWarrants_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBNumberOfSharesIssuedForExerciseOfWarrants_680" xlink:type="arc" order="28" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_NumberOfSharesIssuedForExerciseOfWarrantsValue" xlink:label="loc_CVLBNumberOfSharesIssuedForExerciseOfWarrantsValue_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBNumberOfSharesIssuedForExerciseOfWarrantsValue_680" xlink:type="arc" order="29" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_680" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueStockOptionsExercised_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueStockOptionsExercised_680" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareLiability" xlink:label="loc_CVLBShareLiability_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareLiability_680" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ProceedsFromInvestorsRecordedAsLiabilityToIssueShares" xlink:label="loc_CVLBProceedsFromInvestorsRecordedAsLiabilityToIssueShares_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBProceedsFromInvestorsRecordedAsLiabilityToIssueShares_680" xlink:type="arc" order="33" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaapNetIncomeLossAttributableToNoncontrollingInterest_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLossAttributableToNoncontrollingInterest_680" xlink:type="arc" order="34" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PaymentsForDistributionsToNoncontrollingInterest" xlink:label="loc_CVLBPaymentsForDistributionsToNoncontrollingInterest_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPaymentsForDistributionsToNoncontrollingInterest_680" xlink:type="arc" order="35" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurchasedRemainingInterestPercentage" xlink:label="loc_CVLBPurchasedRemainingInterestPercentage_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPurchasedRemainingInterestPercentage_680" xlink:type="arc" order="36" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_680" xlink:type="arc" order="37" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_680" xlink:type="arc" order="38" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward_680" xlink:type="arc" order="39" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_680" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_RemainingPerformanceOptions" xlink:label="loc_CVLBRemainingPerformanceOptions_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBRemainingPerformanceOptions_680" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_TriggerVestingOfOptions" xlink:label="loc_CVLBTriggerVestingOfOptions_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBTriggerVestingOfOptions_680" xlink:type="arc" order="42" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_680" xlink:type="arc" order="43" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased_680" xlink:type="arc" order="44" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_680" xlink:type="arc" order="45" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_680" xlink:type="arc" order="46" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="loc_us-gaapClassOfWarrantOrRightOutstanding_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightOutstanding_680" xlink:type="arc" order="47" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantStrikePrice" xlink:label="loc_CVLBWarrantStrikePrice_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBWarrantStrikePrice_680" xlink:type="arc" order="48" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantDiscountPricePerShare" xlink:label="loc_CVLBWarrantDiscountPricePerShare_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBWarrantDiscountPricePerShare_680" xlink:type="arc" order="49" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_DeemedDistributionFromWarrantPriceAdjustments" xlink:label="loc_CVLBDeemedDistributionFromWarrantPriceAdjustments_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBDeemedDistributionFromWarrantPriceAdjustments_680" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromWarrantExercises" xlink:label="loc_us-gaapProceedsFromWarrantExercises_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromWarrantExercises_680" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConvertibleNotesPayable" xlink:label="loc_us-gaapConvertibleNotesPayable_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapConvertibleNotesPayable_680" xlink:type="arc" order="52" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_WarrantDescription" xlink:label="loc_CVLBWarrantDescription_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBWarrantDescription_680" xlink:type="arc" order="53" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaapAllocatedShareBasedCompensationExpense_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAllocatedShareBasedCompensationExpense_680" xlink:type="arc" order="54" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_680" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_680" xlink:type="arc" order="55" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StockholdersEquity-ScheduleOfOptionActivityDetails" xlink:title="00000029 - Disclosure - Stockholders&apos; Equity - Schedule of Option Activity (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ServiceBasedStockOptionsMember" xlink:label="loc_CVLBServiceBasedStockOptionsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBServiceBasedStockOptionsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaapPerformanceSharesMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaapPerformanceSharesMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_70" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_70" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_70" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionOutstandingExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionOutstandingExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionOutstandingExercisePrice_70" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice_70" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisedInPeriodExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisedInPeriodExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisedInPeriodExercisePrice_70" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodExercisePrice_70" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePriceBeginning" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePriceBeginning_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePriceBeginning_70" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableExercisePrice_70" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLife_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLife_70" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsGrantedWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsGrantedWeightedAverageContractualLife_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsGrantedWeightedAverageContractualLife_70" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsExercisedWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsExercisedWeightedAverageContractualLife_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsExercisedWeightedAverageContractualLife_70" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsForfeitedAndExpirationsWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsForfeitedAndExpirationsWeightedAverageContractualLife_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsForfeitedAndExpirationsWeightedAverageContractualLife_70" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLifeOne" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLifeOne_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOptionsWeightedAverageContractualLifeOne_70" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1Beginning" xlink:label="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1Beginning_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1Beginning_70" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_70" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_70" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_70" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_70" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_70" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_70" xlink:type="arc" order="26" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/StockholdersEquity-ScheduleOfWarrantOutstandingAndExercisableDetails" xlink:title="00000030 - Disclosure - Stockholders&apos; Equity - Schedule of Warrant Outstanding and Exercisable (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaapWarrantMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapWarrantMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_40" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedAndExpired" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedAndExpired_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisedAndExpired_40" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentExercisable" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentExercisable_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentExercisable_40" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingExercisePrice_40" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodExercisePrice_40" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisedandExpiredInPeriodExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisedandExpiredInPeriodExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisedandExpiredInPeriodExercisePrice_40" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsExercisableExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsExercisableExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsExercisableExercisePrice_40" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLife_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLife_40" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsGrantedWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsGrantedWeightedAverageContractualLife_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsGrantedWeightedAverageContractualLife_40" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsExercisedAndExpiredWeightedAverageContractualLife" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsExercisedAndExpiredWeightedAverageContractualLife_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsExercisedAndExpiredWeightedAverageContractualLife_40" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLifeOne" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLifeOne_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionsWeightedAverageContractualLifeOne_40" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm" xlink:label="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm_40" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm1_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBSharebasedCompensationArrangementBySharebasedPaymentAwardNonOptionsExercisableWeightedAverageRemainingContractualTerm1_40" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingWeightedAverageExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionsOutstandingWeightedAverageExercisePrice_40" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodWeightedAverageExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsGrantsInPeriodWeightedAverageExercisePrice_40" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisesAndExpiredInPeriodWeightedAverageExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisesAndExpiredInPeriodWeightedAverageExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionsExercisesAndExpiredInPeriodWeightedAverageExercisePrice_40" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionExercisableInPeriodWeightedAverageExercisePrice" xlink:label="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionExercisableInPeriodWeightedAverageExercisePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBShareBasedCompensationArrangementsByShareBasedPaymentAwardNonOptionExercisableInPeriodWeightedAverageExercisePrice_40" xlink:type="arc" order="22" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/LeasesDetailsNarrative" xlink:title="00000031 - Disclosure - Leases (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LeaseAgreementMember" xlink:label="loc_CVLBLeaseAgreementMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBLeaseAgreementMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:label="loc_us-gaapLeaseAndRentalExpense_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLeaseAndRentalExpense_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseTermOfContract" xlink:label="loc_us-gaapLesseeOperatingLeaseTermOfContract_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLesseeOperatingLeaseTermOfContract_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo_60" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree_60" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseExpirationDate1" xlink:label="loc_us-gaapLeaseExpirationDate1_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLeaseExpirationDate1_60" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SecurityDeposit" xlink:label="loc_us-gaapSecurityDeposit_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSecurityDeposit_60" xlink:type="arc" order="6" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/Leases-ScheduleOfLeasesDetails" xlink:title="00000032 - Disclosure - Leases - Schedule of Leases (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:title="00000033 - Disclosure - Commitments and Contingencies (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PilarisLaboratoriesLLCMember" xlink:label="loc_CVLBPilarisLaboratoriesLLCMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBPilarisLaboratoriesLLCMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_MALPHABETLLCMember" xlink:label="loc_CVLBMALPHABETLLCMember_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBMALPHABETLLCMember_100" xlink:type="arc" order="101" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CVLBPRMember" xlink:label="loc_CVLBCVLBPRMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_CVLBCVLBPRMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OneEightyDayAnniversaryAgreementMember" xlink:label="loc_CVLBOneEightyDayAnniversaryAgreementMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBOneEightyDayAnniversaryAgreementMember_20" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ThreeSiXFiveDayAnniversaryAgreementMember" xlink:label="loc_CVLBThreeSiXFiveDayAnniversaryAgreementMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBThreeSiXFiveDayAnniversaryAgreementMember_30" xlink:type="arc" order="33" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OneTwentyDayAnniversaryAgreementMember" xlink:label="loc_CVLBOneTwentyDayAnniversaryAgreementMember_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBOneTwentyDayAnniversaryAgreementMember_110" xlink:type="arc" order="112" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ThreeSixtyDayAnniversaryAgreementMember" xlink:label="loc_CVLBThreeSixtyDayAnniversaryAgreementMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_CVLBThreeSixtyDayAnniversaryAgreementMember_120" xlink:type="arc" order="122" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SubscriptionAgreementMember" xlink:label="loc_CVLBSubscriptionAgreementMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBSubscriptionAgreementMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_EmploymentAndConsultingAgreementsMember" xlink:label="loc_CVLBEmploymentAndConsultingAgreementsMember_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBEmploymentAndConsultingAgreementsMember_160" xlink:type="arc" order="161" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CommonStockOneMember" xlink:label="loc_CVLBCommonStockOneMember_130" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBCommonStockOneMember_130" xlink:type="arc" order="132" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CommonStockTwoMember" xlink:label="loc_CVLBCommonStockTwoMember_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBCommonStockTwoMember_140" xlink:type="arc" order="142" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CommonStockThreeMember" xlink:label="loc_CVLBCommonStockThreeMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBCommonStockThreeMember_150" xlink:type="arc" order="152" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PremiumsPercentageAssumedToNet" xlink:label="loc_us-gaapPremiumsPercentageAssumedToNet_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPremiumsPercentageAssumedToNet_200" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntercompanyAgreementsDescription" xlink:label="loc_us-gaapIntercompanyAgreementsDescription_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIntercompanyAgreementsDescription_200" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PerformanceFee" xlink:label="loc_CVLBPerformanceFee_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPerformanceFee_200" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_LicenseFee" xlink:label="loc_CVLBLicenseFee_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBLicenseFee_200" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_200" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:label="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_200" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_200" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PercentageForRoyalty" xlink:label="loc_CVLBPercentageForRoyalty_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPercentageForRoyalty_200" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_200" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_200" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_200" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaapProceedsFromIssuanceOfCommonStock_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOfCommonStock_200" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_ExpiringAgreementDescription" xlink:label="loc_CVLBExpiringAgreementDescription_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBExpiringAgreementDescription_200" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PurchaseCommitments" xlink:label="loc_CVLBPurchaseCommitments_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBPurchaseCommitments_200" xlink:type="arc" order="13" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/RelatedPartyTransactionsDetailsNarrative" xlink:title="00000034 - Disclosure - Related Party Transactions (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PresidentAndCEOMember" xlink:label="loc_CVLBPresidentAndCEOMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBPresidentAndCEOMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ChiefExecutiveOfficerMember" xlink:label="loc_srtChiefExecutiveOfficerMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_srtChiefExecutiveOfficerMember_40" xlink:type="arc" order="42" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_OfficeSpaceMember" xlink:label="loc_CVLBOfficeSpaceMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_CVLBOfficeSpaceMember_0" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PuertoRicoOfficeSpaceMember" xlink:label="loc_CVLBPuertoRicoOfficeSpaceMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_CVLBPuertoRicoOfficeSpaceMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_0" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_10" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_JLSVenturesLLCMember" xlink:label="loc_CVLBJLSVenturesLLCMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBJLSVenturesLLCMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BVGlobalFulfillmentMember" xlink:label="loc_CVLBBVGlobalFulfillmentMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBBVGlobalFulfillmentMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaapBalanceSheetLocationAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapBalanceSheetLocationAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaapBalanceSheetLocationDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBalanceSheetLocationAxis" xlink:to="loc_us-gaapBalanceSheetLocationDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaapBalanceSheetLocationDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBalanceSheetLocationAxis" xlink:to="loc_us-gaapBalanceSheetLocationDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesMember" xlink:label="loc_us-gaapAccountsPayableAndAccruedLiabilitiesMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBalanceSheetLocationDomain" xlink:to="loc_us-gaapAccountsPayableAndAccruedLiabilitiesMember_60" xlink:type="arc" order="63" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRent" xlink:label="loc_us-gaapPaymentsForRent_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPaymentsForRent_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaapRepaymentsOfRelatedPartyDebt_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRepaymentsOfRelatedPartyDebt_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:label="loc_us-gaapDueToRelatedPartiesCurrentAndNoncurrent_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDueToRelatedPartiesCurrentAndNoncurrent_90" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://conversionlabs.com/role/SubsequentEventsDetailsNarrative" xlink:title="00000035 - Disclosure - Subsequent Events (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaapSubsequentEventTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapSubsequentEventTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaapSubsequentEventMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSubsequentEventTypeDomain" xlink:to="loc_us-gaapSubsequentEventMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_SecuritiesPurchaseAgreementMember" xlink:label="loc_CVLBSecuritiesPurchaseAgreementMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_CVLBSecuritiesPurchaseAgreementMember_20" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BTIGLLCMember" xlink:label="loc_CVLBBTIGLLCMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_CVLBBTIGLLCMember_40" xlink:type="arc" order="43" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srtStatementScenarioAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtStatementScenarioAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srtScenarioUnspecifiedDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementScenarioAxis" xlink:to="loc_srtScenarioUnspecifiedDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srtTitleOfIndividualAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtTitleOfIndividualAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtTitleOfIndividualAxis" xlink:to="loc_srtTitleOfIndividualWithRelationshipToEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_BoardOfDirectorsMember" xlink:label="loc_CVLBBoardOfDirectorsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBBoardOfDirectorsMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_InvestorsMember" xlink:label="loc_CVLBInvestorsMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtTitleOfIndividualWithRelationshipToEntityDomain" xlink:to="loc_CVLBInvestorsMember_20" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="loc_us-gaapSubsidiarySaleOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="loc_us-gaapSaleOfStockNameOfTransactionDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:to="loc_us-gaapSaleOfStockNameOfTransactionDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="loc_us-gaapSaleOfStockNameOfTransactionDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:to="loc_us-gaapSaleOfStockNameOfTransactionDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IPOMember" xlink:label="loc_us-gaapIPOMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSaleOfStockNameOfTransactionDomain" xlink:to="loc_us-gaapIPOMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_PAWarrantsMember" xlink:label="loc_CVLBPAWarrantsMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_CVLBPAWarrantsMember_40" xlink:type="arc" order="44" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="loc_us-gaapStockholdersEquityReverseStockSplit_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquityReverseStockSplit_80" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_80" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_80" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_80" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement_80" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="cvlb-20200930.xsd#CVLB_CashCompensationPercentage" xlink:label="loc_CVLBCashCompensationPercentage_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_CVLBCashCompensationPercentage_80" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:label="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight_80" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_80" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable" xlink:label="loc_us-gaapClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable_80" xlink:type="arc" order="8" />
    </link:definitionLink>
</link:linkbase>
