<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- 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 xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByIndustrySector" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByIndustrySector" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByGeographicRegion" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByGeographicRegion" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByCreditQuality" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByCreditQuality" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByMaturity" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByMaturity" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByAssetCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByAssetCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByOtherCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByOtherCategory2" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory2" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#LargestHoldings" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldings" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ProspectusOnly" roleURI="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#RiskOnly" roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#CoregistrantOnly" roleURI="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingAssetCategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#BroadBasedIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#AdditionalIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#IndustrySectorOnly" roleURI="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#GeographicRegionOnly" roleURI="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#CreditQualityOnly" roleURI="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#MaturityOnly" roleURI="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#Other1CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#Other2CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#LargestHoldingOnly" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SalesLoadOnly" roleURI="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ValueMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
    <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://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember" xlink:label="loc_oefAllRisksMember" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_AllocationRiskMember" xlink:label="loc_cstAllocationRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstAllocationRiskMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_InvestmentProcessRiskMember" xlink:label="loc_cstInvestmentProcessRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstInvestmentProcessRiskMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_FundofFundsStructureRiskMember" xlink:label="loc_cstFundofFundsStructureRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstFundofFundsStructureRiskMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_ExchangeTradedFundsRiskMember" xlink:label="loc_cstExchangeTradedFundsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstExchangeTradedFundsRiskMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_AffiliatedUnderlyingFundRiskMember" xlink:label="loc_cstAffiliatedUnderlyingFundRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstAffiliatedUnderlyingFundRiskMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_RisksMember" xlink:label="loc_cstRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstRisksMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_SecuritiesLendingRiskMember" xlink:label="loc_cstSecuritiesLendingRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstSecuritiesLendingRiskMember" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_PortfolioTurnoverRiskMember" xlink:label="loc_cstPortfolioTurnoverRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstPortfolioTurnoverRiskMember" xlink:type="arc" order="70" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_MarketRiskMember" xlink:label="loc_cstMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstMarketRiskMember" xlink:type="arc" order="80" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_EquitySecuritiesRiskMember" xlink:label="loc_cstEquitySecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstEquitySecuritiesRiskMember" xlink:type="arc" order="90" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_PassiveInvestmentRiskMember" xlink:label="loc_cstPassiveInvestmentRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstPassiveInvestmentRiskMember" xlink:type="arc" order="100" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_FixedIncomeSecuritiesRiskMember" xlink:label="loc_cstFixedIncomeSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstFixedIncomeSecuritiesRiskMember" xlink:type="arc" order="110" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_HighYieldBondsHighyieldbondsalsoknownasjunkbondsareconsideredMember" xlink:label="loc_cstHighYieldBondsHighyieldbondsalsoknownasjunkbondsareconsideredMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstHighYieldBondsHighyieldbondsalsoknownasjunkbondsareconsideredMember" xlink:type="arc" order="120" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_DerivativesRiskMember" xlink:label="loc_cstDerivativesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstDerivativesRiskMember" xlink:type="arc" order="130" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_SovereignDebtRiskMember" xlink:label="loc_cstSovereignDebtRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstSovereignDebtRiskMember" xlink:type="arc" order="140" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_ForeignExposureRiskMember" xlink:label="loc_cstForeignExposureRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstForeignExposureRiskMember" xlink:type="arc" order="150" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_RiskOfInvestingInEuropeRiskMember" xlink:label="loc_cstRiskOfInvestingInEuropeRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstRiskOfInvestingInEuropeRiskMember" xlink:type="arc" order="160" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_RiskOfInvestingInJapanRiskMember" xlink:label="loc_cstRiskOfInvestingInJapanRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstRiskOfInvestingInJapanRiskMember" xlink:type="arc" order="170" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_RiskOfInvestingInAsiaRiskMember" xlink:label="loc_cstRiskOfInvestingInAsiaRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstRiskOfInvestingInAsiaRiskMember" xlink:type="arc" order="180" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_IndustryandSectorRiskMember" xlink:label="loc_cstIndustryandSectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstIndustryandSectorRiskMember" xlink:type="arc" order="190" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_LargeCapitalizationCompaniesRiskMember" xlink:label="loc_cstLargeCapitalizationCompaniesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstLargeCapitalizationCompaniesRiskMember" xlink:type="arc" order="200" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_SmallandMidSizedCompaniesRiskMember" xlink:label="loc_cstSmallandMidSizedCompaniesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstSmallandMidSizedCompaniesRiskMember" xlink:type="arc" order="210" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_MortgageandAssetBackedSecuritiesRiskMember" xlink:label="loc_cstMortgageandAssetBackedSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstMortgageandAssetBackedSecuritiesRiskMember" xlink:type="arc" order="220" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_IlliquidInvestmentsRiskMember" xlink:label="loc_cstIlliquidInvestmentsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_cstIlliquidInvestmentsRiskMember" xlink:type="arc" order="230" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_S000052998Member" xlink:label="loc_cstS000052998Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_cstS000052998Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_S000052999Member" xlink:label="loc_cstS000052999Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_cstS000052999Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_S000053000Member" xlink:label="loc_cstS000053000Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_cstS000053000Member" xlink:type="arc" order="20" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="loc_oefShareClassDomain" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_C000166588Member" xlink:label="loc_cstC000166588Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_cstC000166588Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_C000166589Member" xlink:label="loc_cstC000166589Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_cstC000166589Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_C000166590Member" xlink:label="loc_cstC000166590Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_cstC000166590Member" xlink:type="arc" order="20" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_PerformanceMeasureDomain" xlink:label="loc_oefPerformanceMeasureDomain" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_INDEX1Member" xlink:label="loc_cstINDEX1Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_cstINDEX1Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_INDEX2Member" xlink:label="loc_cstINDEX2Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_cstINDEX2Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_INDEX3Member" xlink:label="loc_cstINDEX3Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_cstINDEX3Member" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_INDEX4Member" xlink:label="loc_cstINDEX4Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_cstINDEX4Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="cst-20260430.xsd#cst_INDEX5Member" xlink:label="loc_cstINDEX5Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_cstINDEX5Member" xlink:type="arc" order="40" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
</link:linkbase>