SEC Info  
    Home      Search      My Interests      Help      Sign In      Please Sign In

Boise Cascade Co. – ‘10-Q’ for 6/30/22 – ‘EX-101.DEF’

On:  Monday, 8/1/22, at 4:21pm ET   ·   For:  6/30/22   ·   Accession #:  1328581-22-82   ·   File #:  1-35805

Previous ‘10-Q’:  ‘10-Q’ on 5/5/22 for 3/31/22   ·   Next:  ‘10-Q’ on 10/31/22 for 9/30/22   ·   Latest:  ‘10-Q’ on 5/6/24 for 3/31/24

Find Words in Filings emoji
 
  in    Show  and   Hints

  As Of               Filer                 Filing    For·On·As Docs:Size

 8/01/22  Boise Cascade Co.                 10-Q        6/30/22   67:6.7M

Quarterly Report   —   Form 10-Q

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-Q        Quarterly Report                                    HTML   1.44M 
 2: EX-31.1     Section 302 CEO Certification                       HTML     23K 
 3: EX-31.2     Section 302 CFO Certification                       HTML     23K 
 4: EX-32.1     Section 906 CEO Certification                       HTML     21K 
 5: EX-32.2     Section 906 CFO Certification                       HTML     21K 
11: R1          Document and Entity Information Document            HTML     72K 
12: R2          Consolidated Statements of Operations (Unaudited)   HTML     97K 
13: R3          Consolidated Statements of Comprehensive Income     HTML     40K 
                (Unaudited)                                                      
14: R4          Consolidated Statements of Comprehensive Income     HTML     24K 
                (Unaudited) Parentheticals                                       
15: R5          Consolidated Balance Sheets (Current Period         HTML    164K 
                Unaudited)                                                       
16: R6          Consolidated Balance Sheets (Current Period         HTML     21K 
                Unaudited) Parenthetical                                         
17: R7          Consolidated Statements of Cash Flows (Unaudited)   HTML     96K 
18: R8          Consolidated Statements of Stockholders' Equity     HTML     86K 
                (Unaudited) Statement                                            
19: R9          Nature of Operations and Consolidation (Notes)      HTML     24K 
20: R10         Summary of Significant Accounting Policies (Notes)  HTML     62K 
21: R11         Income Taxes (Notes)                                HTML     24K 
22: R12         Net Income Per Common Share (Notes)                 HTML     42K 
23: R13         Acquisition (Notes)                                 HTML     22K 
24: R14         Debt (Notes)                                        HTML     44K 
25: R15         Leases (Notes)                                      HTML    121K 
26: R16         Stock-Based Compensation (Notes)                    HTML     53K 
27: R17         Stockholders' Equity (Notes)                        HTML     43K 
28: R18         Transactions With Related Party (Notes)             HTML     24K 
29: R19         Segment Information (Notes)                         HTML     83K 
30: R20         Commitments, Legal Proceedings and Contingencies,   HTML     24K 
                and Guarantees (Notes)                                           
31: R21         Summary of Significant Accounting Policies          HTML     55K 
                (Policies)                                                       
32: R22         Summary of Significant Accounting Policies          HTML     44K 
                (Tables)                                                         
33: R23         Net Income Per Common Share (Tables)                HTML     40K 
34: R24         Debt (Tables)                                       HTML     29K 
35: R25         Leases (Tables)                                     HTML     90K 
36: R26         Stock-Based Compensation (Tables)                   HTML     49K 
37: R27         Stockholders' Equity (Tables)                       HTML     35K 
38: R28         Segment Information (Tables)                        HTML     82K 
39: R29         Nature of Operations and Consolidation (Details)    HTML     21K 
40: R30         Summary of Significant Accounting Policies:Revenue  HTML     27K 
                Recognition (Details)                                            
41: R31         Summary of Significant Accounting Policies Summary  HTML     20K 
                of Significant Accounting Policies:Vendor Rebates                
                and Allowances (Details)                                         
42: R32         Summary of Significant Accounting Policies Summary  HTML     30K 
                of Significant Accounting Policies:Leases                        
                (Details)                                                        
43: R33         Summary of Significant Accounting                   HTML     28K 
                Policies:Inventory Valuation (Details)                           
44: R34         Summary of Significant Accounting                   HTML     41K 
                Policies:Property and Equipment (Details)                        
45: R35         Summary of Significant Accounting                   HTML     33K 
                Policies:Financial Instruments (Details)                         
46: R36         Summary of Significant Accounting                   HTML     52K 
                Policies:Interest Rate Risk and Interest Rate                    
                Swaps (Details)                                                  
47: R37         Summary of Significant Accounting                   HTML     28K 
                Policies:Concentration of Credit Risk (Details)                  
48: R38         Income Taxes (Details)                              HTML     30K 
49: R39         Net Income Per Common Share (Details)               HTML     55K 
50: R40         Acquisition (Details)                               HTML     26K 
51: R41         Debt:Summary Table (Details)                        HTML     33K 
52: R42         Debt Asset-Based Revolving Credit Facility          HTML     74K 
                (Details)                                                        
53: R43         Debt:2030 Notes (Details)                           HTML     28K 
54: R44         Debt:Cash Paid for Interest (Details)               HTML     21K 
55: R45         Leases:Costs (Details)                              HTML     36K 
56: R46         Leases:Other Information (Details)                  HTML     97K 
57: R47         Stock-Based Compensation (Details)                  HTML    113K 
58: R48         Stockholders' Equity:Shares and Dividends           HTML     39K 
                (Details)                                                        
59: R49         Stockholders' Equity:AOCI (Details)                 HTML     37K 
60: R50         Transactions With Related Party (Details)           HTML     35K 
61: R51         Segment Information Segment Sales to External       HTML     62K 
                Customers by Product Line (Details)                              
62: R52         Segment Information (Details)                       HTML     44K 
65: XML         IDEA XML File -- Filing Summary                      XML    116K 
63: XML         XBRL Instance -- bcc-20220630_htm                    XML   1.74M 
64: EXCEL       IDEA Workbook of Financial Reports                  XLSX    116K 
 7: EX-101.CAL  XBRL Calculations -- bcc-20220630_cal                XML    175K 
 8: EX-101.DEF  XBRL Definitions -- bcc-20220630_def                 XML    430K 
 9: EX-101.LAB  XBRL Labels -- bcc-20220630_lab                      XML   1.48M 
10: EX-101.PRE  XBRL Presentations -- bcc-20220630_pre               XML    803K 
 6: EX-101.SCH  XBRL Schema -- bcc-20220630                          XSD    128K 
66: JSON        XBRL Instance as JSON Data -- MetaLinks              363±   543K 
67: ZIP         XBRL Zipped Folder -- 0001328581-22-000082-xbrl      Zip    348K 


‘EX-101.DEF’   —   XBRL Definitions — bcc-20220630_def


This Exhibit is an XBRL XML File.


                                                                                                                                                                                
<?xml version="1.0" encoding="windows-1252"?>
<!-- XBRL Document Created with Wdesk from Workiva -->
<!-- Copyright 2022 Workiva -->
<!-- r:96ccd07c-d017-4d6d-a12d-8d2aedbb4ab8,g:43ff1334-b19e-47b8-a7fe-8093429fc5e6 -->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<link:roleRef roleURI="http://www.bc.com/role/ConsolidatedStatementsofStockholdersEquityUnauditedStatement" xlink:type="simple" xlink:href="bcc-20220630.xsd#ConsolidatedStatementsofStockholdersEquityUnauditedStatement"/>
<link:definitionLink xlink:role="http://www.bc.com/role/ConsolidatedStatementsofStockholdersEquityUnauditedStatement" xlink:type="extended" id="i85c5a2e6ed5447989727ffb74c20242a_ConsolidatedStatementsofStockholdersEquityUnauditedStatement">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_ad5f2bc7-3944-4ead-8c5c-687efb2320b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_CommonStockSharesIssued_ad5f2bc7-3944-4ead-8c5c-687efb2320b9" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c2c09424-76d8-4d7e-8ec6-82cd508563b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StockholdersEquity_c2c09424-76d8-4d7e-8ec6-82cd508563b4" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_4a708ee1-1149-4fa0-a768-82a31bb57676" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockCommonShares"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_TreasuryStockCommonShares_4a708ee1-1149-4fa0-a768-82a31bb57676" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_a3786e18-ab3b-4dfd-8020-2a5e9eb4e793" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_a3786e18-ab3b-4dfd-8020-2a5e9eb4e793" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_41b300a0-396e-4559-bb23-a2a30a89adb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_41b300a0-396e-4559-bb23-a2a30a89adb0" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_805ad765-0786-4ab8-abd7-7ce81011cdc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_805ad765-0786-4ab8-abd7-7ce81011cdc2" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_d0b0b522-8370-4c2b-9d40-ba7134a34142" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_d0b0b522-8370-4c2b-9d40-ba7134a34142" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_4712c787-6d1b-4c47-b08b-08782baf2aca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_4712c787-6d1b-4c47-b08b-08782baf2aca" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_aa25dd7e-e629-4618-a624-9acc64bffacd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_DividendsCommonStockCash_aa25dd7e-e629-4618-a624-9acc64bffacd" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_c7e4b39f-4ff1-4fbb-9d8f-14867f4ac1e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsCommonStockCash_aa25dd7e-e629-4618-a624-9acc64bffacd" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_c7e4b39f-4ff1-4fbb-9d8f-14867f4ac1e7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_6deefab3-3178-499c-a6e2-2d117c57d0f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_6deefab3-3178-499c-a6e2-2d117c57d0f2" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_c0ac392b-d838-4b02-bd72-f3852e4c2903" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_c0ac392b-d838-4b02-bd72-f3852e4c2903" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_a7110b15-2d4e-46d2-a6b9-86b03ec0ade8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityOther"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StockholdersEquityOther_a7110b15-2d4e-46d2-a6b9-86b03ec0ade8" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_71ad39e1-f2d7-4f66-9a58-09b41e9617d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_9aa42460-7b1a-43c0-8043-7279610f2b56" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_c7f48124-f41e-46f5-86ff-252dc4cc9b9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockCommonShares"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a4c8633b-a3be-488e-86fc-2feb2a97866d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_811e8fa5-7977-4ec7-8b64-19dff50701c2" xlink:to="loc_us-gaap_StatementTable_a4c8633b-a3be-488e-86fc-2feb2a97866d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_55968c71-9228-4b23-b8ca-d21abf660ae7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a4c8633b-a3be-488e-86fc-2feb2a97866d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_55968c71-9228-4b23-b8ca-d21abf660ae7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_55968c71-9228-4b23-b8ca-d21abf660ae7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_55968c71-9228-4b23-b8ca-d21abf660ae7" xlink:to="loc_us-gaap_EquityComponentDomain_55968c71-9228-4b23-b8ca-d21abf660ae7_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_55968c71-9228-4b23-b8ca-d21abf660ae7" xlink:to="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_8c55006d-d753-4494-851e-0b79f04fdea7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:to="loc_us-gaap_CommonStockMember_8c55006d-d753-4494-851e-0b79f04fdea7" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_b9a8fe30-b7a5-48ba-b4ec-63e4859a63ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockCommonMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:to="loc_us-gaap_TreasuryStockCommonMember_b9a8fe30-b7a5-48ba-b4ec-63e4859a63ea" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_dfa1aefa-d1a8-4766-8ab8-3e0f44a7b354" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_dfa1aefa-d1a8-4766-8ab8-3e0f44a7b354" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5a339a02-2b10-443a-9a29-ddc5d9276e25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5a339a02-2b10-443a-9a29-ddc5d9276e25" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_bcbb08e3-79ca-4d43-898d-cf209d11dacc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_466fef67-c25c-4ef6-ac64-e1f257706769" xlink:to="loc_us-gaap_RetainedEarningsMember_bcbb08e3-79ca-4d43-898d-cf209d11dacc" xlink:type="arc" order="4"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesRevenueRecognitionDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesRevenueRecognitionDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesRevenueRecognitionDetails" xlink:type="extended" id="i1e5f231e70e54e3ba69b201bb99bbbf0_SummaryofSignificantAccountingPoliciesRevenueRecognitionDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_39e96a8c-ba2d-403d-8391-764d00513b05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_c62d17db-7e8d-499a-a91a-793625c4dcda" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_39e96a8c-ba2d-403d-8391-764d00513b05" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_c62d17db-7e8d-499a-a91a-793625c4dcda" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_CustomerRebatesAndAllowances_9788b4c4-2e25-409e-af18-693ce3a70737" xlink:href="bcc-20220630.xsd#bcc_CustomerRebatesAndAllowances"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_39e96a8c-ba2d-403d-8391-764d00513b05" xlink:to="loc_bcc_CustomerRebatesAndAllowances_9788b4c4-2e25-409e-af18-693ce3a70737" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c9da4150-f027-4643-8720-27e39abc1c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_39e96a8c-ba2d-403d-8391-764d00513b05" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c9da4150-f027-4643-8720-27e39abc1c3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_1cbf938d-73e6-4cc3-a06f-163c1a1d9522" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c9da4150-f027-4643-8720-27e39abc1c3e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_1cbf938d-73e6-4cc3-a06f-163c1a1d9522" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1cbf938d-73e6-4cc3-a06f-163c1a1d9522_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1cbf938d-73e6-4cc3-a06f-163c1a1d9522" xlink:to="loc_us-gaap_SegmentDomain_1cbf938d-73e6-4cc3-a06f-163c1a1d9522_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f1fea4b4-08e6-4289-882c-3f8453741793" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1cbf938d-73e6-4cc3-a06f-163c1a1d9522" xlink:to="loc_us-gaap_SegmentDomain_f1fea4b4-08e6-4289-882c-3f8453741793" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BuildingMaterialsDistributionMember_3a1677ef-0855-46cf-99de-7b7ad77adacd" xlink:href="bcc-20220630.xsd#bcc_BuildingMaterialsDistributionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f1fea4b4-08e6-4289-882c-3f8453741793" xlink:to="loc_bcc_BuildingMaterialsDistributionMember_3a1677ef-0855-46cf-99de-7b7ad77adacd" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c9da4150-f027-4643-8720-27e39abc1c3e" xlink:to="loc_srt_ProductOrServiceAxis_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc" xlink:to="loc_srt_ProductsAndServicesDomain_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4bff7d76-7b6e-461c-a43d-bc18928c3bb0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8bd3a979-3a0a-4748-83ff-4ad738dfc4fc" xlink:to="loc_srt_ProductsAndServicesDomain_4bff7d76-7b6e-461c-a43d-bc18928c3bb0" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShippingAndHandlingMember_e3daff86-6011-466b-b9c6-af2cd4f5e641" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShippingAndHandlingMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4bff7d76-7b6e-461c-a43d-bc18928c3bb0" xlink:to="loc_us-gaap_ShippingAndHandlingMember_e3daff86-6011-466b-b9c6-af2cd4f5e641" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesSummaryofSignificantAccountingPoliciesLeasesDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesSummaryofSignificantAccountingPoliciesLeasesDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesSummaryofSignificantAccountingPoliciesLeasesDetails" xlink:type="extended" id="i27a648671cfc42868e3b2e5267a97f9e_SummaryofSignificantAccountingPoliciesSummaryofSignificantAccountingPoliciesLeasesDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_LeaseTermMinimumInitialTermofRealEstateLeases_b7c0efd5-cd9c-4519-b527-a22f9b48aadb" xlink:href="bcc-20220630.xsd#bcc_LeaseTermMinimumInitialTermofRealEstateLeases"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:to="loc_bcc_LeaseTermMinimumInitialTermofRealEstateLeases_b7c0efd5-cd9c-4519-b527-a22f9b48aadb" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_b5fb6288-d055-4151-a0a9-b1004f08f472" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_b5fb6288-d055-4151-a0a9-b1004f08f472" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_RealEstateLeasesCancellationNoticeLatestNotice_586cb1f9-516f-45c0-85a6-a93279ed67c1" xlink:href="bcc-20220630.xsd#bcc_RealEstateLeasesCancellationNoticeLatestNotice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:to="loc_bcc_RealEstateLeasesCancellationNoticeLatestNotice_586cb1f9-516f-45c0-85a6-a93279ed67c1" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_RealEstateLeasesCancellationNoticeEarliestNotice_b12d24dc-c3e8-4f6d-94af-f79b8b8c7ff3" xlink:href="bcc-20220630.xsd#bcc_RealEstateLeasesCancellationNoticeEarliestNotice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:to="loc_bcc_RealEstateLeasesCancellationNoticeEarliestNotice_b12d24dc-c3e8-4f6d-94af-f79b8b8c7ff3" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_942cb1e5-521c-463b-8eb5-e82494379f38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_043c94b8-f934-456e-b6a7-72bb1683628e" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_942cb1e5-521c-463b-8eb5-e82494379f38" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_3447f979-99fa-4956-a554-c811004f194e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_942cb1e5-521c-463b-8eb5-e82494379f38" xlink:to="loc_srt_RangeAxis_3447f979-99fa-4956-a554-c811004f194e" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3447f979-99fa-4956-a554-c811004f194e_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_3447f979-99fa-4956-a554-c811004f194e" xlink:to="loc_srt_RangeMember_3447f979-99fa-4956-a554-c811004f194e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f0fdb52c-8f62-4892-bd51-ae18dd01045a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_3447f979-99fa-4956-a554-c811004f194e" xlink:to="loc_srt_RangeMember_f0fdb52c-8f62-4892-bd51-ae18dd01045a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_00b52c4a-4130-46b7-9394-54ea5e81f6cf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f0fdb52c-8f62-4892-bd51-ae18dd01045a" xlink:to="loc_srt_MinimumMember_00b52c4a-4130-46b7-9394-54ea5e81f6cf" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ce4e6ca7-924b-4a08-89bd-a2447810933d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f0fdb52c-8f62-4892-bd51-ae18dd01045a" xlink:to="loc_srt_MaximumMember_ce4e6ca7-924b-4a08-89bd-a2447810933d" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesPropertyandEquipmentDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesPropertyandEquipmentDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesPropertyandEquipmentDetails" xlink:type="extended" id="i8789b27aaef045f1888539564d0e9c52_SummaryofSignificantAccountingPoliciesPropertyandEquipmentDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_29d15dec-6b7a-4c08-a0c1-b974b31a71a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_04cb397c-7c00-465b-ae78-2ec10445ee84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_29d15dec-6b7a-4c08-a0c1-b974b31a71a1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_04cb397c-7c00-465b-ae78-2ec10445ee84" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_ff9bab71-2f32-4b32-b938-9a2b5940d81f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_29d15dec-6b7a-4c08-a0c1-b974b31a71a1" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_ff9bab71-2f32-4b32-b938-9a2b5940d81f" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_b3deef97-d166-4f7b-b6f9-0cad6ae47082" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_29d15dec-6b7a-4c08-a0c1-b974b31a71a1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_b3deef97-d166-4f7b-b6f9-0cad6ae47082" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f0a07f3d-9d8e-42f8-8693-9c14426350fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_29d15dec-6b7a-4c08-a0c1-b974b31a71a1" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f0a07f3d-9d8e-42f8-8693-9c14426350fe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38800339-01e5-4aa2-8106-1412cc653bd3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f0a07f3d-9d8e-42f8-8693-9c14426350fe" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38800339-01e5-4aa2-8106-1412cc653bd3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_38800339-01e5-4aa2-8106-1412cc653bd3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38800339-01e5-4aa2-8106-1412cc653bd3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_38800339-01e5-4aa2-8106-1412cc653bd3_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38800339-01e5-4aa2-8106-1412cc653bd3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_9283a418-ea07-45a3-b117-162d94b9b043" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LandMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_us-gaap_LandMember_9283a418-ea07-45a3-b117-162d94b9b043" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingMember_7948195e-b380-47ff-8ba6-c4adb3744491" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BuildingMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_us-gaap_BuildingMember_7948195e-b380-47ff-8ba6-c4adb3744491" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BuildingandLeaseholdImprovementsMember_2ae37d0a-d0de-484b-bad5-a0774783a856" xlink:href="bcc-20220630.xsd#bcc_BuildingandLeaseholdImprovementsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_bcc_BuildingandLeaseholdImprovementsMember_2ae37d0a-d0de-484b-bad5-a0774783a856" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_MobileequipmentinformationtechnologyandofficefurnitureMember_c6a7c910-e25a-4fe0-8829-243974b4f86d" xlink:href="bcc-20220630.xsd#bcc_MobileequipmentinformationtechnologyandofficefurnitureMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_bcc_MobileequipmentinformationtechnologyandofficefurnitureMember_c6a7c910-e25a-4fe0-8829-243974b4f86d" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_c322c870-1da3-465d-ac9a-fd78576b2136" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MachineryAndEquipmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_c322c870-1da3-465d-ac9a-fd78576b2136" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_a30b2b41-e826-4a2d-ae44-90762e18a16c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a32eae18-3410-4d51-b94e-cec24f05084c" xlink:to="loc_us-gaap_ConstructionInProgressMember_a30b2b41-e826-4a2d-ae44-90762e18a16c" xlink:type="arc" order="5"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesFinancialInstrumentsDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesFinancialInstrumentsDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesFinancialInstrumentsDetails" xlink:type="extended" id="i0ba69066e74d4addb4287ea6e0fdf8c8_SummaryofSignificantAccountingPoliciesFinancialInstrumentsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_566bfe57-91d6-44d0-90ae-af1cc31bb4aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_3a8617de-9f4f-4168-a5e7-7b76bb076b40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_566bfe57-91d6-44d0-90ae-af1cc31bb4aa" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_3a8617de-9f4f-4168-a5e7-7b76bb076b40" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_4f652632-af03-48bf-84a4-63a27d5d9db5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_3a8617de-9f4f-4168-a5e7-7b76bb076b40" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_4f652632-af03-48bf-84a4-63a27d5d9db5" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_942cd187-f5b1-48b1-83be-542456425159" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_3a8617de-9f4f-4168-a5e7-7b76bb076b40" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_942cd187-f5b1-48b1-83be-542456425159" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_566bfe57-91d6-44d0-90ae-af1cc31bb4aa" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_2e010df9-25ef-42ac-8798-669d218bb99d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_2e010df9-25ef-42ac-8798-669d218bb99d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_2e010df9-25ef-42ac-8798-669d218bb99d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_2e010df9-25ef-42ac-8798-669d218bb99d" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_2e010df9-25ef-42ac-8798-669d218bb99d_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_3606361c-2064-4ad7-a7dd-60c63b432590" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_2e010df9-25ef-42ac-8798-669d218bb99d" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_3606361c-2064-4ad7-a7dd-60c63b432590" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_581f1f88-a13a-4d58-bd5d-6d26e83ad4ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_3606361c-2064-4ad7-a7dd-60c63b432590" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_581f1f88-a13a-4d58-bd5d-6d26e83ad4ea" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6bf96004-dd51-4a9a-a2d1-3493b0c6587a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6bf96004-dd51-4a9a-a2d1-3493b0c6587a" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6bf96004-dd51-4a9a-a2d1-3493b0c6587a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6bf96004-dd51-4a9a-a2d1-3493b0c6587a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6bf96004-dd51-4a9a-a2d1-3493b0c6587a_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53d0b72a-3989-4d75-b38d-e61b3406ea36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6bf96004-dd51-4a9a-a2d1-3493b0c6587a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53d0b72a-3989-4d75-b38d-e61b3406ea36" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_2990d7b4-bbd2-45d4-9af4-cf60db7e2b16" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53d0b72a-3989-4d75-b38d-e61b3406ea36" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_2990d7b4-bbd2-45d4-9af4-cf60db7e2b16" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_5a02d0ef-aef1-4283-9ebd-064454e4467f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_53d0b72a-3989-4d75-b38d-e61b3406ea36" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_5a02d0ef-aef1-4283-9ebd-064454e4467f" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_e95a55df-9207-41f7-9719-2ef825ae97b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_e95a55df-9207-41f7-9719-2ef825ae97b7" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_e95a55df-9207-41f7-9719-2ef825ae97b7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_e95a55df-9207-41f7-9719-2ef825ae97b7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_e95a55df-9207-41f7-9719-2ef825ae97b7_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_4f1ab1db-be9a-451b-a23a-27fa169cf7eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_e95a55df-9207-41f7-9719-2ef825ae97b7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_4f1ab1db-be9a-451b-a23a-27fa169cf7eb" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_9e1c2522-9e2d-43e9-ba38-3f1515d10bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_4f1ab1db-be9a-451b-a23a-27fa169cf7eb" xlink:to="loc_us-gaap_MoneyMarketFundsMember_9e1c2522-9e2d-43e9-ba38-3f1515d10bc1" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_0c6fa845-1353-4996-944c-96e932f02ee1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_0c6fa845-1353-4996-944c-96e932f02ee1" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0c6fa845-1353-4996-944c-96e932f02ee1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0c6fa845-1353-4996-944c-96e932f02ee1" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0c6fa845-1353-4996-944c-96e932f02ee1_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_95ded66d-64ec-44a6-8c00-c5664e1dc76b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0c6fa845-1353-4996-944c-96e932f02ee1" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_95ded66d-64ec-44a6-8c00-c5664e1dc76b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_131d389c-2f5a-4b6b-a09e-5d45c41b626e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_95ded66d-64ec-44a6-8c00-c5664e1dc76b" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_131d389c-2f5a-4b6b-a09e-5d45c41b626e" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_cc693f7a-bc0c-44f8-afe8-d5d6c88e0490" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_95ded66d-64ec-44a6-8c00-c5664e1dc76b" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_cc693f7a-bc0c-44f8-afe8-d5d6c88e0490" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_26aa2b73-2741-47c2-95b5-3e672e99ab76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_95ded66d-64ec-44a6-8c00-c5664e1dc76b" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_26aa2b73-2741-47c2-95b5-3e672e99ab76" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_93686877-9ae4-4f28-86d6-af4a84f9247a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_746669b9-d688-4855-b58c-a59cb49e73d9" xlink:to="loc_us-gaap_DebtInstrumentAxis_93686877-9ae4-4f28-86d6-af4a84f9247a" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_93686877-9ae4-4f28-86d6-af4a84f9247a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_93686877-9ae4-4f28-86d6-af4a84f9247a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_93686877-9ae4-4f28-86d6-af4a84f9247a_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_473f451f-4469-4e3e-ab6c-be90f30d5bfe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_93686877-9ae4-4f28-86d6-af4a84f9247a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_473f451f-4469-4e3e-ab6c-be90f30d5bfe" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_A4875SeniorNotesDue2030Member_cec7c457-59bd-4178-884c-cde777a49efb" xlink:href="bcc-20220630.xsd#bcc_A4875SeniorNotesDue2030Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_473f451f-4469-4e3e-ab6c-be90f30d5bfe" xlink:to="loc_bcc_A4875SeniorNotesDue2030Member_cec7c457-59bd-4178-884c-cde777a49efb" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesInterestRateRiskandInterestRateSwapsDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesInterestRateRiskandInterestRateSwapsDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesInterestRateRiskandInterestRateSwapsDetails" xlink:type="extended" id="i12bfdd54f9a24055867cd2b67713155c_SummaryofSignificantAccountingPoliciesInterestRateRiskandInterestRateSwapsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_9bfbfd74-1d40-4e61-afa7-6a739839a138" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_9bfbfd74-1d40-4e61-afa7-6a739839a138" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_c467ec08-ab87-4abc-a0e4-f4c6c5cf31e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_c467ec08-ab87-4abc-a0e4-f4c6c5cf31e3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_c5b43e76-5f47-4c06-bd54-cd45e5e760cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_DerivativeNotionalAmount_c5b43e76-5f47-4c06-bd54-cd45e5e760cc" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_952ee85f-bd6f-4e99-9679-757ca22ca3b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFixedInterestRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_952ee85f-bd6f-4e99-9679-757ca22ca3b7" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeForwardInterestRate_e6af1799-7be5-4255-b2b4-3b6c5e8ef26e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeForwardInterestRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_DerivativeForwardInterestRate_e6af1799-7be5-4255-b2b4-3b6c5e8ef26e" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue_e720feb2-d3eb-4d02-819d-a8f2b4e518b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue_e720feb2-d3eb-4d02-819d-a8f2b4e518b8" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue_a73620c3-8cfd-476a-9621-e7aebc275b69" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue_a73620c3-8cfd-476a-9621-e7aebc275b69" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_NumberOfDerivativeInstrument_1add5e6b-69e5-4109-9872-1438e308dbf4" xlink:href="bcc-20220630.xsd#bcc_NumberOfDerivativeInstrument"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_bcc_NumberOfDerivativeInstrument_1add5e6b-69e5-4109-9872-1438e308dbf4" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_0fb091e5-aada-49c6-90a1-603cebfc6bed" xlink:to="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_f9337dc2-86d8-4e4d-b152-84259ef98196" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_DebtInstrumentAxis_f9337dc2-86d8-4e4d-b152-84259ef98196" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f9337dc2-86d8-4e4d-b152-84259ef98196_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_f9337dc2-86d8-4e4d-b152-84259ef98196" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f9337dc2-86d8-4e4d-b152-84259ef98196_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_a8fd8781-de8e-4479-aa3d-7f1ffa1ba6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_f9337dc2-86d8-4e4d-b152-84259ef98196" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_a8fd8781-de8e-4479-aa3d-7f1ffa1ba6ae" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_ABLTermLoanDue2025Member_02120586-b492-42ec-a353-3b297cb1ad3c" xlink:href="bcc-20220630.xsd#bcc_ABLTermLoanDue2025Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_a8fd8781-de8e-4479-aa3d-7f1ffa1ba6ae" xlink:to="loc_bcc_ABLTermLoanDue2025Member_02120586-b492-42ec-a353-3b297cb1ad3c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_cfe75d0a-edf6-43bb-83fb-f9ef47380f93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_VariableRateAxis_cfe75d0a-edf6-43bb-83fb-f9ef47380f93" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_cfe75d0a-edf6-43bb-83fb-f9ef47380f93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_cfe75d0a-edf6-43bb-83fb-f9ef47380f93" xlink:to="loc_us-gaap_VariableRateDomain_cfe75d0a-edf6-43bb-83fb-f9ef47380f93_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_de8fcef3-fe92-415c-940b-03790b17fc05" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_cfe75d0a-edf6-43bb-83fb-f9ef47380f93" xlink:to="loc_us-gaap_VariableRateDomain_de8fcef3-fe92-415c-940b-03790b17fc05" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_49913d40-74d9-40c5-94fd-aab79c975f71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_de8fcef3-fe92-415c-940b-03790b17fc05" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_49913d40-74d9-40c5-94fd-aab79c975f71" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_784b627c-d6c5-4e06-b557-62356f37e78e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_784b627c-d6c5-4e06-b557-62356f37e78e" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_784b627c-d6c5-4e06-b557-62356f37e78e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_784b627c-d6c5-4e06-b557-62356f37e78e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_784b627c-d6c5-4e06-b557-62356f37e78e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_eb06df49-c401-4b3c-bead-17e50afc7bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_784b627c-d6c5-4e06-b557-62356f37e78e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_eb06df49-c401-4b3c-bead-17e50afc7bf2" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_3c5f45a7-745c-4f01-a27c-ff34c25713de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_eb06df49-c401-4b3c-bead-17e50afc7bf2" xlink:to="loc_us-gaap_InterestRateSwapMember_3c5f45a7-745c-4f01-a27c-ff34c25713de" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_InterestRateSwap50millionnotionalamountfixedat1.007Member_0499b223-df13-4404-8561-cdcc660156a6" xlink:href="bcc-20220630.xsd#bcc_InterestRateSwap50millionnotionalamountfixedat1.007Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_eb06df49-c401-4b3c-bead-17e50afc7bf2" xlink:to="loc_bcc_InterestRateSwap50millionnotionalamountfixedat1.007Member_0499b223-df13-4404-8561-cdcc660156a6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_InterestRateSwap50MillionNotionalAmountFixedAt039Member_9571b885-c4cc-43b5-b679-47eac7bdf12f" xlink:href="bcc-20220630.xsd#bcc_InterestRateSwap50MillionNotionalAmountFixedAt039Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_eb06df49-c401-4b3c-bead-17e50afc7bf2" xlink:to="loc_bcc_InterestRateSwap50MillionNotionalAmountFixedAt039Member_9571b885-c4cc-43b5-b679-47eac7bdf12f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_9bb9c148-04db-4504-8a4a-d7e320ef6111" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_HedgingDesignationAxis_9bb9c148-04db-4504-8a4a-d7e320ef6111" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_9bb9c148-04db-4504-8a4a-d7e320ef6111_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_9bb9c148-04db-4504-8a4a-d7e320ef6111" xlink:to="loc_us-gaap_HedgingDesignationDomain_9bb9c148-04db-4504-8a4a-d7e320ef6111_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_385a0e85-5beb-404f-88c4-d3f882a26237" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_9bb9c148-04db-4504-8a4a-d7e320ef6111" xlink:to="loc_us-gaap_HedgingDesignationDomain_385a0e85-5beb-404f-88c4-d3f882a26237" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_b9a49558-3c39-456a-9aca-fef4525f11f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_385a0e85-5beb-404f-88c4-d3f882a26237" xlink:to="loc_us-gaap_NondesignatedMember_b9a49558-3c39-456a-9aca-fef4525f11f1" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8055ca95-a243-4852-8ed3-ed41b30020d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1d58db27-2bcb-49e5-bf62-a2b4ce63e50f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8055ca95-a243-4852-8ed3-ed41b30020d4" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_1f802aa3-71a2-4cd8-a881-c248874d4691" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8055ca95-a243-4852-8ed3-ed41b30020d4" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_1f802aa3-71a2-4cd8-a881-c248874d4691" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_88cd1466-ed25-445e-bb3b-8e9c14c77966" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_04124c51-331b-4618-ab78-bf6cd9a80a12" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_88cd1466-ed25-445e-bb3b-8e9c14c77966" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_88cd1466-ed25-445e-bb3b-8e9c14c77966_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_88cd1466-ed25-445e-bb3b-8e9c14c77966" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_88cd1466-ed25-445e-bb3b-8e9c14c77966_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7997d985-61b4-4c37-8856-5d50550d4814" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_88cd1466-ed25-445e-bb3b-8e9c14c77966" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7997d985-61b4-4c37-8856-5d50550d4814" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_3426631e-4cfe-4fb6-b069-3fdcb11c9973" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_7997d985-61b4-4c37-8856-5d50550d4814" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_3426631e-4cfe-4fb6-b069-3fdcb11c9973" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_c0190506-50fb-4e89-89ea-4348f146d125" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_7997d985-61b4-4c37-8856-5d50550d4814" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_c0190506-50fb-4e89-89ea-4348f146d125" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="extended" id="i925a4ef3621a4fcf859735a556f46c6b_SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_f3a09a5c-6890-4003-94af-39e6d1ffeeaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_b72cd8a3-c2aa-4e04-8470-11881ddb7434" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_f3a09a5c-6890-4003-94af-39e6d1ffeeaf" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_b72cd8a3-c2aa-4e04-8470-11881ddb7434" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_3cb52abe-8185-459e-b289-c8bc4f714828" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_f3a09a5c-6890-4003-94af-39e6d1ffeeaf" xlink:to="loc_us-gaap_ConcentrationRiskTable_3cb52abe-8185-459e-b289-c8bc4f714828" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_99c71248-6a52-4488-ad5b-b2a037cbed07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_3cb52abe-8185-459e-b289-c8bc4f714828" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_99c71248-6a52-4488-ad5b-b2a037cbed07" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_99c71248-6a52-4488-ad5b-b2a037cbed07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_99c71248-6a52-4488-ad5b-b2a037cbed07" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_99c71248-6a52-4488-ad5b-b2a037cbed07_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fc7617d7-b4a9-472d-9061-a992f2c4f3db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_99c71248-6a52-4488-ad5b-b2a037cbed07" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fc7617d7-b4a9-472d-9061-a992f2c4f3db" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_33d37b0e-c1c0-43fa-b78c-8e2ca5123a41" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fc7617d7-b4a9-472d-9061-a992f2c4f3db" xlink:to="loc_us-gaap_AccountsReceivableMember_33d37b0e-c1c0-43fa-b78c-8e2ca5123a41" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_bf056b7c-3dfa-4f78-8959-8f2252bd1548" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_3cb52abe-8185-459e-b289-c8bc4f714828" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_bf056b7c-3dfa-4f78-8959-8f2252bd1548" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_bf056b7c-3dfa-4f78-8959-8f2252bd1548_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bf056b7c-3dfa-4f78-8959-8f2252bd1548" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_bf056b7c-3dfa-4f78-8959-8f2252bd1548_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_2e75c0b4-9846-4be4-ae17-575fbb5b4330" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bf056b7c-3dfa-4f78-8959-8f2252bd1548" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_2e75c0b4-9846-4be4-ae17-575fbb5b4330" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_725b94f5-b081-49db-a7fe-c24de0dc9a7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditConcentrationRiskMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_2e75c0b4-9846-4be4-ae17-575fbb5b4330" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_725b94f5-b081-49db-a7fe-c24de0dc9a7b" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_3cb52abe-8185-459e-b289-c8bc4f714828" xlink:to="loc_srt_MajorCustomersAxis_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf" xlink:to="loc_srt_NameOfMajorCustomerDomain_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_10465a0e-8f38-4db6-a090-c2fec6972e59" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_50c5b1d8-8156-4cc9-84fd-9e807eb16fdf" xlink:to="loc_srt_NameOfMajorCustomerDomain_10465a0e-8f38-4db6-a090-c2fec6972e59" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_CustomerOneMember_b8a2351e-4937-40c3-89c2-fb5eba49bc9c" xlink:href="bcc-20220630.xsd#bcc_CustomerOneMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_10465a0e-8f38-4db6-a090-c2fec6972e59" xlink:to="loc_bcc_CustomerOneMember_b8a2351e-4937-40c3-89c2-fb5eba49bc9c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_CustomerTwoMember_b774ed6d-8328-4056-aa41-789a3e60ba61" xlink:href="bcc-20220630.xsd#bcc_CustomerTwoMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_10465a0e-8f38-4db6-a090-c2fec6972e59" xlink:to="loc_bcc_CustomerTwoMember_b774ed6d-8328-4056-aa41-789a3e60ba61" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/NetIncomePerCommonShareDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#NetIncomePerCommonShareDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/NetIncomePerCommonShareDetails" xlink:type="extended" id="iad7080267a8548a8834bc62594d5315e_NetIncomePerCommonShareDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_d9dbb0d4-88e4-49c5-b46b-13fb0da90d28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d9aed0f7-3814-4efa-89cb-7d5ae54b16f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_d9dbb0d4-88e4-49c5-b46b-13fb0da90d28" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d9aed0f7-3814-4efa-89cb-7d5ae54b16f4" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_ccb8ae3e-47d4-4aa5-893d-b2e5f8f56f1a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_d9dbb0d4-88e4-49c5-b46b-13fb0da90d28" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_ccb8ae3e-47d4-4aa5-893d-b2e5f8f56f1a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_1990de7a-c975-4f14-9255-4aa3ba9581ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_ccb8ae3e-47d4-4aa5-893d-b2e5f8f56f1a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_1990de7a-c975-4f14-9255-4aa3ba9581ff" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_1990de7a-c975-4f14-9255-4aa3ba9581ff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_1990de7a-c975-4f14-9255-4aa3ba9581ff" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_1990de7a-c975-4f14-9255-4aa3ba9581ff_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d5c16481-0f8a-43eb-8490-6237bd1a6471" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_1990de7a-c975-4f14-9255-4aa3ba9581ff" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d5c16481-0f8a-43eb-8490-6237bd1a6471" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_24d79be6-4dee-4c6a-9e75-9861d14aa5c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockCompensationPlanMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d5c16481-0f8a-43eb-8490-6237bd1a6471" xlink:to="loc_us-gaap_StockCompensationPlanMember_24d79be6-4dee-4c6a-9e75-9861d14aa5c6" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/AcquisitionDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#AcquisitionDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/AcquisitionDetails" xlink:type="extended" id="i0e63631aa1ee4d559bbcf36a705d5e0c_AcquisitionDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionLineItems_952cd1c0-419d-42aa-aa8d-082b28a68dd7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetAcquisitionLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_b19947ef-34b8-4106-bb57-cdf6b3de41c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionLineItems_952cd1c0-419d-42aa-aa8d-082b28a68dd7" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_b19947ef-34b8-4106-bb57-cdf6b3de41c3" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BusinessCombinationConsiderationAssumedWorkingCapital_a894c2d3-7b06-4088-a4df-e23d455156dd" xlink:href="bcc-20220630.xsd#bcc_BusinessCombinationConsiderationAssumedWorkingCapital"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionLineItems_952cd1c0-419d-42aa-aa8d-082b28a68dd7" xlink:to="loc_bcc_BusinessCombinationConsiderationAssumedWorkingCapital_a894c2d3-7b06-4088-a4df-e23d455156dd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionTable_a3d77c76-343b-43a0-841f-ba2d6f9cba88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetAcquisitionTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AssetAcquisitionLineItems_952cd1c0-419d-42aa-aa8d-082b28a68dd7" xlink:to="loc_us-gaap_AssetAcquisitionTable_a3d77c76-343b-43a0-841f-ba2d6f9cba88" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_64d62869-81b6-4656-acf3-a7066ee0fef2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AssetAcquisitionTable_a3d77c76-343b-43a0-841f-ba2d6f9cba88" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_64d62869-81b6-4656-acf3-a7066ee0fef2" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_64d62869-81b6-4656-acf3-a7066ee0fef2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_64d62869-81b6-4656-acf3-a7066ee0fef2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_64d62869-81b6-4656-acf3-a7066ee0fef2_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_df152d61-acfb-43cc-b0dc-a5eccd2a78b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_64d62869-81b6-4656-acf3-a7066ee0fef2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_df152d61-acfb-43cc-b0dc-a5eccd2a78b3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_WoodProductsCoastalPlywoodFacilitiesMember_b90951ee-a395-4702-9488-60dbbe62c048" xlink:href="bcc-20220630.xsd#bcc_WoodProductsCoastalPlywoodFacilitiesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_df152d61-acfb-43cc-b0dc-a5eccd2a78b3" xlink:to="loc_bcc_WoodProductsCoastalPlywoodFacilitiesMember_b90951ee-a395-4702-9488-60dbbe62c048" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/DebtSummaryTableDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#DebtSummaryTableDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/DebtSummaryTableDetails" xlink:type="extended" id="ib56dd6c545d9406c8c532623e22a35e4_DebtSummaryTableDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_90e2a441-efb6-419e-8976-704d2551cd53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_54373e5c-e3f8-419e-a184-561e20fdfa2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_90e2a441-efb6-419e-8976-704d2551cd53" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_54373e5c-e3f8-419e-a184-561e20fdfa2c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_44123b14-8981-40fb-96ec-109065262a5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_90e2a441-efb6-419e-8976-704d2551cd53" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_44123b14-8981-40fb-96ec-109065262a5e" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_00933000-d346-41ec-a71a-7ba5ac63f6f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_90e2a441-efb6-419e-8976-704d2551cd53" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_00933000-d346-41ec-a71a-7ba5ac63f6f5" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_c6270c8e-a7ee-4daf-b4af-f8f600172958" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_90e2a441-efb6-419e-8976-704d2551cd53" xlink:to="loc_us-gaap_DebtInstrumentTable_c6270c8e-a7ee-4daf-b4af-f8f600172958" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_92e027a4-4259-4b02-837d-aa84b454577f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c6270c8e-a7ee-4daf-b4af-f8f600172958" xlink:to="loc_us-gaap_DebtInstrumentAxis_92e027a4-4259-4b02-837d-aa84b454577f" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_92e027a4-4259-4b02-837d-aa84b454577f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_92e027a4-4259-4b02-837d-aa84b454577f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_92e027a4-4259-4b02-837d-aa84b454577f_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_784bb027-6b4c-488f-9f34-36b0e7351a3c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_92e027a4-4259-4b02-837d-aa84b454577f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_784bb027-6b4c-488f-9f34-36b0e7351a3c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_4772eb9b-f27e-4493-a840-bb1a50285d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_784bb027-6b4c-488f-9f34-36b0e7351a3c" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_4772eb9b-f27e-4493-a840-bb1a50285d3e" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_ABLTermLoanDue2025Member_565bc0bf-0cb4-43d2-a087-1b63036461f3" xlink:href="bcc-20220630.xsd#bcc_ABLTermLoanDue2025Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_784bb027-6b4c-488f-9f34-36b0e7351a3c" xlink:to="loc_bcc_ABLTermLoanDue2025Member_565bc0bf-0cb4-43d2-a087-1b63036461f3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_A4875SeniorNotesDue2030Member_6fb971f7-6138-4e0d-bf3f-29059abd79e9" xlink:href="bcc-20220630.xsd#bcc_A4875SeniorNotesDue2030Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_784bb027-6b4c-488f-9f34-36b0e7351a3c" xlink:to="loc_bcc_A4875SeniorNotesDue2030Member_6fb971f7-6138-4e0d-bf3f-29059abd79e9" xlink:type="arc" order="2"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/DebtAssetBasedRevolvingCreditFacilityDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#DebtAssetBasedRevolvingCreditFacilityDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/DebtAssetBasedRevolvingCreditFacilityDetails" xlink:type="extended" id="i243a2c2fb0084d579d08dcc4808415a0_DebtAssetBasedRevolvingCreditFacilityDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_81e28786-bc4c-441b-9e8e-6c6519b4e132" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_81e28786-bc4c-441b-9e8e-6c6519b4e132" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Fixedchargecoverageratiorequirementifavailabilityfallsbelow10ofaggregatelendingcommitmentsasapercent_0971e5ad-0b2a-4a98-b463-e6d811c460fb" xlink:href="bcc-20220630.xsd#bcc_Fixedchargecoverageratiorequirementifavailabilityfallsbelow10ofaggregatelendingcommitmentsasapercent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_Fixedchargecoverageratiorequirementifavailabilityfallsbelow10ofaggregatelendingcommitmentsasapercent_0971e5ad-0b2a-4a98-b463-e6d811c460fb" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Thresholdofavailabilityasapercentageofaggregatelendingcommitmentsbelowwhich11fixedchargecoverageratiomustbemet_50296fe9-43c0-4784-a782-20cd9db613a3" xlink:href="bcc-20220630.xsd#bcc_Thresholdofavailabilityasapercentageofaggregatelendingcommitmentsbelowwhich11fixedchargecoverageratiomustbemet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_Thresholdofavailabilityasapercentageofaggregatelendingcommitmentsbelowwhich11fixedchargecoverageratiomustbemet_50296fe9-43c0-4784-a782-20cd9db613a3" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Thresholdofavailabilitybelowwhich11fixedchargecoverageratiomustbemet_1342f2f4-f9fa-4896-9cd7-a023191a2ef3" xlink:href="bcc-20220630.xsd#bcc_Thresholdofavailabilitybelowwhich11fixedchargecoverageratiomustbemet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_Thresholdofavailabilitybelowwhich11fixedchargecoverageratiomustbemet_1342f2f4-f9fa-4896-9cd7-a023191a2ef3" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_90a8a272-0010-4e9c-89ff-ab72c087de91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_90a8a272-0010-4e9c-89ff-ab72c087de91" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_DividendrestrictionsinglethresholdpercentageofaggregateRevolverCommitments_1946444b-b9a6-4e54-bc5d-52edcbcad289" xlink:href="bcc-20220630.xsd#bcc_DividendrestrictionsinglethresholdpercentageofaggregateRevolverCommitments"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_DividendrestrictionsinglethresholdpercentageofaggregateRevolverCommitments_1946444b-b9a6-4e54-bc5d-52edcbcad289" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_DividendrestrictioncombinationthresholdspercentageofaggregateRevolverCommitments_be781a1c-4a63-496d-b260-2f557aed51fa" xlink:href="bcc-20220630.xsd#bcc_DividendrestrictioncombinationthresholdspercentageofaggregateRevolverCommitments"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_DividendrestrictioncombinationthresholdspercentageofaggregateRevolverCommitments_be781a1c-4a63-496d-b260-2f557aed51fa" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Dividendrestrictioncombinationthresholdsfixedchargecoverageratioasapercent_c1642aed-b295-41d3-be34-499db9d0e8eb" xlink:href="bcc-20220630.xsd#bcc_Dividendrestrictioncombinationthresholdsfixedchargecoverageratioasapercent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_bcc_Dividendrestrictioncombinationthresholdsfixedchargecoverageratioasapercent_c1642aed-b295-41d3-be34-499db9d0e8eb" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_aec8061f-53e0-432e-9644-add8669cae59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_aec8061f-53e0-432e-9644-add8669cae59" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_af66514f-65fc-48e3-a8a0-4d4917cbd979" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_af66514f-65fc-48e3-a8a0-4d4917cbd979" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_6bb7183a-e25f-43d2-97f6-0cae562fef70" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LineOfCredit_6bb7183a-e25f-43d2-97f6-0cae562fef70" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_531771d6-fc41-4398-a290-50d037c6396f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_531771d6-fc41-4398-a290-50d037c6396f" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumtermNotesAbstract_b2e122cd-7de4-44be-b937-51cd62bc498e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MediumtermNotesAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_MediumtermNotesAbstract_b2e122cd-7de4-44be-b937-51cd62bc498e" xlink:type="arc" order="12"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_eb2beccf-c420-4f22-b911-c96ffa9eb485" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MediumtermNotesAbstract_b2e122cd-7de4-44be-b937-51cd62bc498e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_eb2beccf-c420-4f22-b911-c96ffa9eb485" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_946c35c7-ea0a-4a89-8112-c5952cb3369f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MediumtermNotesAbstract_b2e122cd-7de4-44be-b937-51cd62bc498e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_946c35c7-ea0a-4a89-8112-c5952cb3369f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_DebtInstrumentInterestRateDuringPeriodWithPatronageCredits_94d1a979-50c4-4d3a-80f3-7d667701f1e9" xlink:href="bcc-20220630.xsd#bcc_DebtInstrumentInterestRateDuringPeriodWithPatronageCredits"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MediumtermNotesAbstract_b2e122cd-7de4-44be-b937-51cd62bc498e" xlink:to="loc_bcc_DebtInstrumentInterestRateDuringPeriodWithPatronageCredits_94d1a979-50c4-4d3a-80f3-7d667701f1e9" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_f48b598a-9e5c-4f29-b226-9a932a9bc005" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_419758be-5792-41ed-8d67-75d56d656a00" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_f48b598a-9e5c-4f29-b226-9a932a9bc005" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_044bc706-d4fd-4665-8232-ab7aff4d635c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_f48b598a-9e5c-4f29-b226-9a932a9bc005" xlink:to="loc_us-gaap_DebtInstrumentAxis_044bc706-d4fd-4665-8232-ab7aff4d635c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_044bc706-d4fd-4665-8232-ab7aff4d635c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_044bc706-d4fd-4665-8232-ab7aff4d635c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_044bc706-d4fd-4665-8232-ab7aff4d635c_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_70c17848-a06e-4520-bc31-41a50001a435" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_044bc706-d4fd-4665-8232-ab7aff4d635c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_70c17848-a06e-4520-bc31-41a50001a435" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_AssetBasedCreditFacilityMember_2527c1ad-31a4-4ff8-aab6-5958d8197f59" xlink:href="bcc-20220630.xsd#bcc_AssetBasedCreditFacilityMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_70c17848-a06e-4520-bc31-41a50001a435" xlink:to="loc_bcc_AssetBasedCreditFacilityMember_2527c1ad-31a4-4ff8-aab6-5958d8197f59" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_cf71c708-2496-4fe4-a71f-7978c14b0456" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_AssetBasedCreditFacilityMember_2527c1ad-31a4-4ff8-aab6-5958d8197f59" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_cf71c708-2496-4fe4-a71f-7978c14b0456" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_ABLTermLoanDue2025Member_0c8f5efa-48b9-4194-9784-68af8478fd35" xlink:href="bcc-20220630.xsd#bcc_ABLTermLoanDue2025Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_AssetBasedCreditFacilityMember_2527c1ad-31a4-4ff8-aab6-5958d8197f59" xlink:to="loc_bcc_ABLTermLoanDue2025Member_0c8f5efa-48b9-4194-9784-68af8478fd35" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_39866291-b047-4137-92b7-ad8443bfe04f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_f48b598a-9e5c-4f29-b226-9a932a9bc005" xlink:to="loc_us-gaap_VariableRateAxis_39866291-b047-4137-92b7-ad8443bfe04f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_39866291-b047-4137-92b7-ad8443bfe04f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_39866291-b047-4137-92b7-ad8443bfe04f" xlink:to="loc_us-gaap_VariableRateDomain_39866291-b047-4137-92b7-ad8443bfe04f_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_b1f7eb3a-aa20-4073-b263-921673d70277" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_39866291-b047-4137-92b7-ad8443bfe04f" xlink:to="loc_us-gaap_VariableRateDomain_b1f7eb3a-aa20-4073-b263-921673d70277" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_75e2357c-21cb-4898-be45-9b99b5e31916" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_b1f7eb3a-aa20-4073-b263-921673d70277" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_75e2357c-21cb-4898-be45-9b99b5e31916" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_537fc3c5-9058-4fe0-984e-f3e512a747e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BaseRateMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_b1f7eb3a-aa20-4073-b263-921673d70277" xlink:to="loc_us-gaap_BaseRateMember_537fc3c5-9058-4fe0-984e-f3e512a747e1" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_680dd4bf-dbca-4c98-b291-36477328fbcd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_f48b598a-9e5c-4f29-b226-9a932a9bc005" xlink:to="loc_srt_RangeAxis_680dd4bf-dbca-4c98-b291-36477328fbcd" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_680dd4bf-dbca-4c98-b291-36477328fbcd_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_680dd4bf-dbca-4c98-b291-36477328fbcd" xlink:to="loc_srt_RangeMember_680dd4bf-dbca-4c98-b291-36477328fbcd_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_fd778c84-b0be-425b-967b-ac06b764fd79" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_680dd4bf-dbca-4c98-b291-36477328fbcd" xlink:to="loc_srt_RangeMember_fd778c84-b0be-425b-967b-ac06b764fd79" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_98fd9c50-dc27-49ef-94fa-a3cc156218e4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fd778c84-b0be-425b-967b-ac06b764fd79" xlink:to="loc_srt_MinimumMember_98fd9c50-dc27-49ef-94fa-a3cc156218e4" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_9cc1a2f2-f9d1-4792-b5fc-aacaa7ce0f84" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fd778c84-b0be-425b-967b-ac06b764fd79" xlink:to="loc_srt_MaximumMember_9cc1a2f2-f9d1-4792-b5fc-aacaa7ce0f84" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/Debt2030NotesDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#Debt2030NotesDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/Debt2030NotesDetails" xlink:type="extended" id="if7f415f95f7f4e35b42370faa4419b1e_Debt2030NotesDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_2c560a74-0c8b-468c-8b13-0c5d8eaf64a9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_aed2fc2e-06da-4e56-b273-71bb543568c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2c560a74-0c8b-468c-8b13-0c5d8eaf64a9" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_aed2fc2e-06da-4e56-b273-71bb543568c8" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ec36dffc-76b1-4258-a007-1ff9d23a9bbf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2c560a74-0c8b-468c-8b13-0c5d8eaf64a9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ec36dffc-76b1-4258-a007-1ff9d23a9bbf" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Dividendrestrictioninterestcoverageratioasapercent_550929e6-539b-4ee0-bba9-b9a719fd6543" xlink:href="bcc-20220630.xsd#bcc_Dividendrestrictioninterestcoverageratioasapercent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2c560a74-0c8b-468c-8b13-0c5d8eaf64a9" xlink:to="loc_bcc_Dividendrestrictioninterestcoverageratioasapercent_550929e6-539b-4ee0-bba9-b9a719fd6543" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_1851cdc4-6ac4-4f13-a324-e0c0bf007f0d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2c560a74-0c8b-468c-8b13-0c5d8eaf64a9" xlink:to="loc_us-gaap_DebtInstrumentTable_1851cdc4-6ac4-4f13-a324-e0c0bf007f0d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1851cdc4-6ac4-4f13-a324-e0c0bf007f0d" xlink:to="loc_us-gaap_DebtInstrumentAxis_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_89733def-e3f7-416b-b9ce-c51c781032db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_77c2c1fa-5f60-4317-b35d-bb592c6a1e6d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_89733def-e3f7-416b-b9ce-c51c781032db" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_A4875SeniorNotesDue2030Member_5aeb94d4-6003-48f5-ab9a-83ba0c3d3160" xlink:href="bcc-20220630.xsd#bcc_A4875SeniorNotesDue2030Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_89733def-e3f7-416b-b9ce-c51c781032db" xlink:to="loc_bcc_A4875SeniorNotesDue2030Member_5aeb94d4-6003-48f5-ab9a-83ba0c3d3160" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1851cdc4-6ac4-4f13-a324-e0c0bf007f0d" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d9de35d5-573f-4c41-bf9c-6151b3f50710" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e8be35cd-32f5-4e9e-9529-bee5cb42a5fd" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d9de35d5-573f-4c41-bf9c-6151b3f50710" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_53a31504-e535-45b2-ba22-e55cc5c45928" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d9de35d5-573f-4c41-bf9c-6151b3f50710" xlink:to="loc_us-gaap_SeniorNotesMember_53a31504-e535-45b2-ba22-e55cc5c45928" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/StockBasedCompensationDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#StockBasedCompensationDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/StockBasedCompensationDetails" xlink:type="extended" id="i585452d1a24740c996b6985004f6fa91_StockBasedCompensationDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_Numberoftypesofstockbasedawardsgrantedintypes_33208248-f90d-45a0-b745-a71ab5aba025" xlink:href="bcc-20220630.xsd#bcc_Numberoftypesofstockbasedawardsgrantedintypes"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_Numberoftypesofstockbasedawardsgrantedintypes_33208248-f90d-45a0-b745-a71ab5aba025" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountminimum_15b9e9fb-0b4c-4944-9d6b-9240aea91656" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountminimum"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountminimum_15b9e9fb-0b4c-4944-9d6b-9240aea91656" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountmaximum_fb1248d5-b309-44f7-ab25-89330d3764d4" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountmaximum"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageofROICtargetamountmaximum_fb1248d5-b309-44f7-ab25-89330d3764d4" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountminimum_a3ad5954-7e1f-4327-bc37-c6c26bae37ae" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountminimum"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountminimum_a3ad5954-7e1f-4327-bc37-c6c26bae37ae" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountmaximum_288ee414-ed85-4277-abe0-5175be1087f6" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountmaximum"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesthatcouldbeawardedasapercentageoftargetamountmaximum_288ee414-ed85-4277-abe0-5175be1087f6" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesTargetPercentageEarnedasapercentageofROICtargetamount_d9200265-624d-47a2-9885-87e47879eaf0" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesTargetPercentageEarnedasapercentageofROICtargetamount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesTargetPercentageEarnedasapercentageofROICtargetamount_d9200265-624d-47a2-9885-87e47879eaf0" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PerformanceSharesTargetPercentageEarned_66822cdd-a025-4b7a-8e5a-4a29b7a7b50e" xlink:href="bcc-20220630.xsd#bcc_PerformanceSharesTargetPercentageEarned"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_PerformanceSharesTargetPercentageEarned_66822cdd-a025-4b7a-8e5a-4a29b7a7b50e" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_864d59c2-a7fe-4a27-8da7-25767a4a1c7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_864d59c2-a7fe-4a27-8da7-25767a4a1c7c" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_NumberofEqualTranchesforAnnualVestingGrantDate_6759b000-4e4e-42cf-aa66-222283398d3a" xlink:href="bcc-20220630.xsd#bcc_NumberofEqualTranchesforAnnualVestingGrantDate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_bcc_NumberofEqualTranchesforAnnualVestingGrantDate_6759b000-4e4e-42cf-aa66-222283398d3a" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4044bf27-4f21-4340-baab-62d5468fce0c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4044bf27-4f21-4340-baab-62d5468fce0c" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_5121fdab-b7f9-4db6-b6f7-1dee7eadaf3f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_5121fdab-b7f9-4db6-b6f7-1dee7eadaf3f" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_fc09b310-1ba8-417a-a42c-8f92f6fa4326" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_fc09b310-1ba8-417a-a42c-8f92f6fa4326" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_d24dcac9-30c0-4c04-817d-ed3ade60ef04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_d24dcac9-30c0-4c04-817d-ed3ade60ef04" xlink:type="arc" order="12"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_d1bcac41-84d4-4c09-9ba0-b6abf47115de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_d1bcac41-84d4-4c09-9ba0-b6abf47115de" xlink:type="arc" order="13"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:type="arc" order="14"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2bdcbcd8-eb54-4da5-9f24-9385cf00bb2a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2bdcbcd8-eb54-4da5-9f24-9385cf00bb2a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_fc83270a-d5ee-4a16-b437-b85ef9f0ddba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_fc83270a-d5ee-4a16-b437-b85ef9f0ddba" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueup_29f45a61-0cdb-4a96-8eb8-1c57479cde3f" xlink:href="bcc-20220630.xsd#bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueup"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:to="loc_bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueup_29f45a61-0cdb-4a96-8eb8-1c57479cde3f" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_99d5c15b-d5b2-4103-ad79-ead90cfb8c13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_99d5c15b-d5b2-4103-ad79-ead90cfb8c13" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b57b83d2-aa0e-48bd-bf95-26abac81f132" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35859286-3aa6-449b-93a4-3656801445d3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b57b83d2-aa0e-48bd-bf95-26abac81f132" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_4a7294c3-847e-43a7-aa69-4ee3db7bf7ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:type="arc" order="15"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0574d1a8-1e68-455f-b1ec-5465a7c670d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0574d1a8-1e68-455f-b1ec-5465a7c670d5" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_425182a4-a6b7-425a-a267-bf86093dd3fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_425182a4-a6b7-425a-a267-bf86093dd3fa" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueupWeightedAverageGrantDateFairValue_abc1e21b-5efb-48b3-9b29-430ce8f24616" xlink:href="bcc-20220630.xsd#bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueupWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:to="loc_bcc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsPerformanceTrueupWeightedAverageGrantDateFairValue_abc1e21b-5efb-48b3-9b29-430ce8f24616" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_17b5d7b0-970c-48cd-a272-4a00ecce8276" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_17b5d7b0-970c-48cd-a272-4a00ecce8276" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_c45d831f-49ee-4a4d-9a8b-0366a85327b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_65b3b152-168e-4f34-a07b-987b16126c7a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_c45d831f-49ee-4a4d-9a8b-0366a85327b6" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_f59be178-5c86-426d-977e-83c36b5abae8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_46354b40-9e3a-4b86-b01e-b03fd491fbbe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7d895a3a-eadf-4a09-a2d8-8bcb6eb7dbe8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_46354b40-9e3a-4b86-b01e-b03fd491fbbe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_26359a0d-571e-41a0-ab40-f7c00fab0f95" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_46354b40-9e3a-4b86-b01e-b03fd491fbbe" xlink:to="loc_srt_TitleOfIndividualAxis_26359a0d-571e-41a0-ab40-f7c00fab0f95" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_26359a0d-571e-41a0-ab40-f7c00fab0f95_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_26359a0d-571e-41a0-ab40-f7c00fab0f95" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_26359a0d-571e-41a0-ab40-f7c00fab0f95_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3692eec7-c255-4f3a-99f8-5fa7c2e43e9d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_26359a0d-571e-41a0-ab40-f7c00fab0f95" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3692eec7-c255-4f3a-99f8-5fa7c2e43e9d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_OfficersAndOtherEmployeesAndNonemploymentDirectorsMember_1b8210d8-8fc7-45fa-a312-fbdb96104e29" xlink:href="bcc-20220630.xsd#bcc_OfficersAndOtherEmployeesAndNonemploymentDirectorsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3692eec7-c255-4f3a-99f8-5fa7c2e43e9d" xlink:to="loc_bcc_OfficersAndOtherEmployeesAndNonemploymentDirectorsMember_1b8210d8-8fc7-45fa-a312-fbdb96104e29" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_NonemployeeDirectorsMember_ce315431-29c3-4243-8b86-9d98f8faefc1" xlink:href="bcc-20220630.xsd#bcc_NonemployeeDirectorsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_OfficersAndOtherEmployeesAndNonemploymentDirectorsMember_1b8210d8-8fc7-45fa-a312-fbdb96104e29" xlink:to="loc_bcc_NonemployeeDirectorsMember_ce315431-29c3-4243-8b86-9d98f8faefc1" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_OfficersandotheremployeesMember_8e15c8f0-4a6d-4625-96ed-f3d5a88e5528" xlink:href="bcc-20220630.xsd#bcc_OfficersandotheremployeesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_OfficersAndOtherEmployeesAndNonemploymentDirectorsMember_1b8210d8-8fc7-45fa-a312-fbdb96104e29" xlink:to="loc_bcc_OfficersandotheremployeesMember_8e15c8f0-4a6d-4625-96ed-f3d5a88e5528" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_OfficerMember_9292b77d-ae14-491f-8deb-d472169698cd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OfficerMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_OfficersandotheremployeesMember_8e15c8f0-4a6d-4625-96ed-f3d5a88e5528" xlink:to="loc_srt_OfficerMember_9292b77d-ae14-491f-8deb-d472169698cd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_OtheremployeesMember_2d97c9b9-45c9-4405-951b-38eab2799964" xlink:href="bcc-20220630.xsd#bcc_OtheremployeesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bcc_OfficersandotheremployeesMember_8e15c8f0-4a6d-4625-96ed-f3d5a88e5528" xlink:to="loc_bcc_OtheremployeesMember_2d97c9b9-45c9-4405-951b-38eab2799964" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_44f776db-180c-466b-980e-316ef5a98155" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_46354b40-9e3a-4b86-b01e-b03fd491fbbe" xlink:to="loc_us-gaap_AwardTypeAxis_44f776db-180c-466b-980e-316ef5a98155" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_44f776db-180c-466b-980e-316ef5a98155_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_44f776db-180c-466b-980e-316ef5a98155" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_44f776db-180c-466b-980e-316ef5a98155_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a15ce293-642f-4e9f-a4c6-7ce836f8a33c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_44f776db-180c-466b-980e-316ef5a98155" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a15ce293-642f-4e9f-a4c6-7ce836f8a33c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_e751d0f2-14fc-4562-91b9-d5a794c789c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PerformanceSharesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a15ce293-642f-4e9f-a4c6-7ce836f8a33c" xlink:to="loc_us-gaap_PerformanceSharesMember_e751d0f2-14fc-4562-91b9-d5a794c789c8" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_694c1cc4-ba20-4990-9f96-9e02865feebc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a15ce293-642f-4e9f-a4c6-7ce836f8a33c" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_694c1cc4-ba20-4990-9f96-9e02865feebc" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/StockholdersEquitySharesandDividendsDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#StockholdersEquitySharesandDividendsDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/StockholdersEquitySharesandDividendsDetails" xlink:type="extended" id="i59c1918d5b5548a288457d4fff1ce448_StockholdersEquitySharesandDividendsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_464c2851-6c87-453f-ac4b-8733152e304a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPayableDateDeclaredDayMonthAndYear"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_464c2851-6c87-453f-ac4b-8733152e304a" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_6690eacd-ecb2-4c4c-8756-974e9fb1eade" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_6690eacd-ecb2-4c4c-8756-974e9fb1eade" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendPayableDateToBePaidDayMonthAndYear_55f1704e-7849-44e3-aa4d-d73cf898eb66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendPayableDateToBePaidDayMonthAndYear"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_DividendPayableDateToBePaidDayMonthAndYear_55f1704e-7849-44e3-aa4d-d73cf898eb66" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_b88e6622-291c-4063-9716-5fed3dd482f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsPayableDateOfRecordDayMonthAndYear"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_b88e6622-291c-4063-9716-5fed3dd482f5" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_d0f8d108-9981-435b-b288-44e07c8d7f09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_d0f8d108-9981-435b-b288-44e07c8d7f09" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_af361367-ad90-4e6e-8817-3b47c6d3a1cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_af361367-ad90-4e6e-8817-3b47c6d3a1cf" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_2050c934-961d-4935-94a6-6fc26eedf2db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_2050c934-961d-4935-94a6-6fc26eedf2db" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_4285b897-30af-4a79-a736-43ea86a58765" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_31d4c0c5-3b5b-4ae2-ab91-0e41d3963eb5" xlink:to="loc_us-gaap_SubsequentEventTable_4285b897-30af-4a79-a736-43ea86a58765" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_2ae9b168-fd42-43c6-951d-9e827b9b0b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_4285b897-30af-4a79-a736-43ea86a58765" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_2ae9b168-fd42-43c6-951d-9e827b9b0b8d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_2ae9b168-fd42-43c6-951d-9e827b9b0b8d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_2ae9b168-fd42-43c6-951d-9e827b9b0b8d" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_2ae9b168-fd42-43c6-951d-9e827b9b0b8d_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_64c70f0b-9943-4aed-b343-e2f025c853c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_2ae9b168-fd42-43c6-951d-9e827b9b0b8d" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_64c70f0b-9943-4aed-b343-e2f025c853c4" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_ced6cacd-aea7-4fe5-9ec4-e7321be8295e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_64c70f0b-9943-4aed-b343-e2f025c853c4" xlink:to="loc_us-gaap_SubsequentEventMember_ced6cacd-aea7-4fe5-9ec4-e7321be8295e" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_4285b897-30af-4a79-a736-43ea86a58765" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_f4b866b2-6178-4c3c-95d6-8fe3a7ea8ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_3b5bfd79-d885-441b-bcaf-e5db3a50cc3b" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_f4b866b2-6178-4c3c-95d6-8fe3a7ea8ec0" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BCCommonStockRepurchaseProgramMember_904f8301-c2e7-40a3-afd2-d56aeccb2931" xlink:href="bcc-20220630.xsd#bcc_BCCommonStockRepurchaseProgramMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_f4b866b2-6178-4c3c-95d6-8fe3a7ea8ec0" xlink:to="loc_bcc_BCCommonStockRepurchaseProgramMember_904f8301-c2e7-40a3-afd2-d56aeccb2931" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/StockholdersEquityAOCIDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#StockholdersEquityAOCIDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/StockholdersEquityAOCIDetails" xlink:type="extended" id="i5755b616857b4335a5e3d740920293ac_StockholdersEquityAOCIDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_96384f2e-fc76-4cc9-8905-d35dbda3422d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_96384f2e-fc76-4cc9-8905-d35dbda3422d" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4f5c9375-3f01-4b51-badf-5b77c7e25699" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:to="loc_us-gaap_StockholdersEquity_4f5c9375-3f01-4b51-badf-5b77c7e25699" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_1d0f596a-f167-4f4f-a2ae-f156a253aeaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_1d0f596a-f167-4f4f-a2ae-f156a253aeaf" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationBeforeTax_cf4a9b80-61f4-41fe-a5d9-ac0fdfdf3571" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationBeforeTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationBeforeTax_cf4a9b80-61f4-41fe-a5d9-ac0fdfdf3571" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_50c1790b-4900-4f66-9001-b50ead969c91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_246bf100-ac01-47cc-890a-90487f84e6b8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_50c1790b-4900-4f66-9001-b50ead969c91" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_571a17c8-3e11-41e0-88d8-35027818ce06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5e4a32f9-14b0-4514-a3c7-fbfd30f973db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_96384f2e-fc76-4cc9-8905-d35dbda3422d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5e4a32f9-14b0-4514-a3c7-fbfd30f973db" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6cfb995d-8224-4fd5-a020-e7ed8324c4e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5e4a32f9-14b0-4514-a3c7-fbfd30f973db" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6cfb995d-8224-4fd5-a020-e7ed8324c4e7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6cfb995d-8224-4fd5-a020-e7ed8324c4e7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6cfb995d-8224-4fd5-a020-e7ed8324c4e7" xlink:to="loc_us-gaap_EquityComponentDomain_6cfb995d-8224-4fd5-a020-e7ed8324c4e7_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6212ef0f-60e8-411d-a46b-f325b6710974" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6cfb995d-8224-4fd5-a020-e7ed8324c4e7" xlink:to="loc_us-gaap_EquityComponentDomain_6212ef0f-60e8-411d-a46b-f325b6710974" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8e90a8a1-a87e-4fa9-bf71-042dfb690382" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6212ef0f-60e8-411d-a46b-f325b6710974" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8e90a8a1-a87e-4fa9-bf71-042dfb690382" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/TransactionsWithRelatedPartyDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#TransactionsWithRelatedPartyDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/TransactionsWithRelatedPartyDetails" xlink:type="extended" id="i8e3180a8dc0b45e7b35576fa3f707ae9_TransactionsWithRelatedPartyDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_ef268f66-b89c-45b2-8977-de98d16688e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityOwnershipPercentage_336fbc71-7a23-425f-8dd2-27dc7a6c8537" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityOwnershipPercentage"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ef268f66-b89c-45b2-8977-de98d16688e6" xlink:to="loc_us-gaap_VariableInterestEntityOwnershipPercentage_336fbc71-7a23-425f-8dd2-27dc7a6c8537" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromRelatedParties_60ae145c-5136-4abd-afd1-c583ae7d96ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromRelatedParties"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ef268f66-b89c-45b2-8977-de98d16688e6" xlink:to="loc_us-gaap_RevenueFromRelatedParties_60ae145c-5136-4abd-afd1-c583ae7d96ab" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_d9c01567-ecfd-4930-a01e-285caac7e956" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ef268f66-b89c-45b2-8977-de98d16688e6" xlink:to="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_d9c01567-ecfd-4930-a01e-285caac7e956" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ef268f66-b89c-45b2-8977-de98d16688e6" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_1a2f93da-e323-4974-87fa-d6f2b823bafe" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:to="loc_srt_OwnershipAxis_1a2f93da-e323-4974-87fa-d6f2b823bafe" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_1a2f93da-e323-4974-87fa-d6f2b823bafe_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_1a2f93da-e323-4974-87fa-d6f2b823bafe" xlink:to="loc_srt_OwnershipDomain_1a2f93da-e323-4974-87fa-d6f2b823bafe_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_9f69e5d3-569f-47c1-a53d-b3dde597ecc7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_1a2f93da-e323-4974-87fa-d6f2b823bafe" xlink:to="loc_srt_OwnershipDomain_9f69e5d3-569f-47c1-a53d-b3dde597ecc7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_LouisianaTimberProcurementCompanyLLCMember_5da73fe0-67ce-4ab8-9780-7db00400e20c" xlink:href="bcc-20220630.xsd#bcc_LouisianaTimberProcurementCompanyLLCMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_9f69e5d3-569f-47c1-a53d-b3dde597ecc7" xlink:to="loc_bcc_LouisianaTimberProcurementCompanyLLCMember_5da73fe0-67ce-4ab8-9780-7db00400e20c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_b08c38d9-5d15-46bc-ae3c-49d727898026" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:to="loc_dei_LegalEntityAxis_b08c38d9-5d15-46bc-ae3c-49d727898026" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b08c38d9-5d15-46bc-ae3c-49d727898026_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_b08c38d9-5d15-46bc-ae3c-49d727898026" xlink:to="loc_dei_EntityDomain_b08c38d9-5d15-46bc-ae3c-49d727898026_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_665507d4-773d-4e04-baee-1c29c1bcfa45" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_b08c38d9-5d15-46bc-ae3c-49d727898026" xlink:to="loc_dei_EntityDomain_665507d4-773d-4e04-baee-1c29c1bcfa45" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PackagingCorporationofAmericaPCAMember_cc6ba57c-0c59-4360-86ed-29c4d671816f" xlink:href="bcc-20220630.xsd#bcc_PackagingCorporationofAmericaPCAMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_665507d4-773d-4e04-baee-1c29c1bcfa45" xlink:to="loc_bcc_PackagingCorporationofAmericaPCAMember_cc6ba57c-0c59-4360-86ed-29c4d671816f" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ff21af1e-2099-483f-9d95-2b782ffb746e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ff21af1e-2099-483f-9d95-2b782ffb746e" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_ff21af1e-2099-483f-9d95-2b782ffb746e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ff21af1e-2099-483f-9d95-2b782ffb746e" xlink:to="loc_us-gaap_RelatedPartyDomain_ff21af1e-2099-483f-9d95-2b782ffb746e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_3f60c320-f124-4797-b3a2-3f6d3c0308aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ff21af1e-2099-483f-9d95-2b782ffb746e" xlink:to="loc_us-gaap_RelatedPartyDomain_3f60c320-f124-4797-b3a2-3f6d3c0308aa" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_e1e5303a-8e36-4640-b8fc-54c7602be279" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3f60c320-f124-4797-b3a2-3f6d3c0308aa" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_e1e5303a-8e36-4640-b8fc-54c7602be279" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_c3d17857-6339-4c9c-875c-80f455e1a37b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3f60c320-f124-4797-b3a2-3f6d3c0308aa" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_c3d17857-6339-4c9c-875c-80f455e1a37b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_02d6b008-0cd5-404d-8916-fb3ea519ad56" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_ae6ae565-07d4-4110-8ec0-008d10f29519" xlink:to="loc_srt_ConsolidatedEntitiesAxis_02d6b008-0cd5-404d-8916-fb3ea519ad56" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_02d6b008-0cd5-404d-8916-fb3ea519ad56_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_02d6b008-0cd5-404d-8916-fb3ea519ad56" xlink:to="loc_srt_ConsolidatedEntitiesDomain_02d6b008-0cd5-404d-8916-fb3ea519ad56_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_8addc552-4a2d-4d71-81eb-6b36bcb2623b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_02d6b008-0cd5-404d-8916-fb3ea519ad56" xlink:to="loc_srt_ConsolidatedEntitiesDomain_8addc552-4a2d-4d71-81eb-6b36bcb2623b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_69156bda-bf1f-43f4-806c-4ef12b0c3d79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_8addc552-4a2d-4d71-81eb-6b36bcb2623b" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_69156bda-bf1f-43f4-806c-4ef12b0c3d79" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SegmentInformationSegmentSalestoExternalCustomersbyProductLineDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SegmentInformationSegmentSalestoExternalCustomersbyProductLineDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SegmentInformationSegmentSalestoExternalCustomersbyProductLineDetails" xlink:type="extended" id="i424be70343154144b18b76ec2de82cac_SegmentInformationSegmentSalestoExternalCustomersbyProductLineDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_256c4648-2773-4b39-b363-efa8c9a2a1b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ee8a817c-0eb5-42c6-b1c4-7980b016e262" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_256c4648-2773-4b39-b363-efa8c9a2a1b0" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ee8a817c-0eb5-42c6-b1c4-7980b016e262" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_IntersegmentEWPSalesVolumesAsPercentagetoTotalEWPSalesVolumes_6232a45e-c312-4c0f-b473-4393cd175973" xlink:href="bcc-20220630.xsd#bcc_IntersegmentEWPSalesVolumesAsPercentagetoTotalEWPSalesVolumes"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_256c4648-2773-4b39-b363-efa8c9a2a1b0" xlink:to="loc_bcc_IntersegmentEWPSalesVolumesAsPercentagetoTotalEWPSalesVolumes_6232a45e-c312-4c0f-b473-4393cd175973" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3eb8469a-b068-402d-b35d-c2537f92a692" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_256c4648-2773-4b39-b363-efa8c9a2a1b0" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3eb8469a-b068-402d-b35d-c2537f92a692" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_a6323698-f6f5-4cb4-894d-f1e894632b93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3eb8469a-b068-402d-b35d-c2537f92a692" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_a6323698-f6f5-4cb4-894d-f1e894632b93" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a6323698-f6f5-4cb4-894d-f1e894632b93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a6323698-f6f5-4cb4-894d-f1e894632b93" xlink:to="loc_us-gaap_SegmentDomain_a6323698-f6f5-4cb4-894d-f1e894632b93_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ed64424e-89cc-4cab-973a-926c8e4da39c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a6323698-f6f5-4cb4-894d-f1e894632b93" xlink:to="loc_us-gaap_SegmentDomain_ed64424e-89cc-4cab-973a-926c8e4da39c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_WoodProductsMember_aba4f46c-2a32-4749-955d-28225a38bd2b" xlink:href="bcc-20220630.xsd#bcc_WoodProductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ed64424e-89cc-4cab-973a-926c8e4da39c" xlink:to="loc_bcc_WoodProductsMember_aba4f46c-2a32-4749-955d-28225a38bd2b" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BuildingMaterialsDistributionMember_e668bcc8-081c-4021-b73d-efe5cb8a9cd9" xlink:href="bcc-20220630.xsd#bcc_BuildingMaterialsDistributionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ed64424e-89cc-4cab-973a-926c8e4da39c" xlink:to="loc_bcc_BuildingMaterialsDistributionMember_e668bcc8-081c-4021-b73d-efe5cb8a9cd9" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_6cf23e59-c325-46c8-93bc-fc12c288f05d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3eb8469a-b068-402d-b35d-c2537f92a692" xlink:to="loc_srt_ProductOrServiceAxis_6cf23e59-c325-46c8-93bc-fc12c288f05d" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_6cf23e59-c325-46c8-93bc-fc12c288f05d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_6cf23e59-c325-46c8-93bc-fc12c288f05d" xlink:to="loc_srt_ProductsAndServicesDomain_6cf23e59-c325-46c8-93bc-fc12c288f05d_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_6cf23e59-c325-46c8-93bc-fc12c288f05d" xlink:to="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_LaminatedVeneerLumberMember_153d1f14-8ba8-4c21-b276-537473d4bb4b" xlink:href="bcc-20220630.xsd#bcc_LaminatedVeneerLumberMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_LaminatedVeneerLumberMember_153d1f14-8ba8-4c21-b276-537473d4bb4b" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_IjoistsMember_56390d6b-080c-42cc-ad1e-8b7d6ed466d7" xlink:href="bcc-20220630.xsd#bcc_IjoistsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_IjoistsMember_56390d6b-080c-42cc-ad1e-8b7d6ed466d7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_OtherEngineeredWoodProductsMember_0f9fdce7-acae-40c8-880d-0c321b682839" xlink:href="bcc-20220630.xsd#bcc_OtherEngineeredWoodProductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_OtherEngineeredWoodProductsMember_0f9fdce7-acae-40c8-880d-0c321b682839" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_PlywoodAndVeneerMember_e857f847-d72f-4f07-9401-b7a98433036f" xlink:href="bcc-20220630.xsd#bcc_PlywoodAndVeneerMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_PlywoodAndVeneerMember_e857f847-d72f-4f07-9401-b7a98433036f" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_LumberMember_cfeb705d-bc4e-4539-9c56-bebe9025519b" xlink:href="bcc-20220630.xsd#bcc_LumberMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_LumberMember_cfeb705d-bc4e-4539-9c56-bebe9025519b" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_ByproductsMember_eb7b110d-0baa-456c-aace-dabd4b09262b" xlink:href="bcc-20220630.xsd#bcc_ByproductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_ByproductsMember_eb7b110d-0baa-456c-aace-dabd4b09262b" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_OtherWoodProductsMember_58a0ed3d-ac5e-4b04-bf7e-265d9965d6d1" xlink:href="bcc-20220630.xsd#bcc_OtherWoodProductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_OtherWoodProductsMember_58a0ed3d-ac5e-4b04-bf7e-265d9965d6d1" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_CommodityProductLineMember_decf9b02-6bd4-4988-9a54-d759c7e11f3c" xlink:href="bcc-20220630.xsd#bcc_CommodityProductLineMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_CommodityProductLineMember_decf9b02-6bd4-4988-9a54-d759c7e11f3c" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_GeneralLineMember_29554533-0b5f-4250-9cc8-27d1e5818853" xlink:href="bcc-20220630.xsd#bcc_GeneralLineMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_GeneralLineMember_29554533-0b5f-4250-9cc8-27d1e5818853" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_EngineeredWoodProductsMember_d6c27953-526b-4189-a6d5-d61e7ffdebf7" xlink:href="bcc-20220630.xsd#bcc_EngineeredWoodProductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11023b0a-6e03-4d8f-bf7e-c3ab73c95b21" xlink:to="loc_bcc_EngineeredWoodProductsMember_d6c27953-526b-4189-a6d5-d61e7ffdebf7" xlink:type="arc" order="9"/>
</link:definitionLink>
<link:roleRef roleURI="http://www.bc.com/role/SegmentInformationDetails" xlink:type="simple" xlink:href="bcc-20220630.xsd#SegmentInformationDetails"/>
<link:definitionLink xlink:role="http://www.bc.com/role/SegmentInformationDetails" xlink:type="extended" id="ic43360e6ce2d4a3895f6cab613e24bc7_SegmentInformationDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_98dbbe33-cf8d-48d3-86b3-3675c90f4c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_16924b9b-d656-4957-8c75-96436ea4fac3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_98dbbe33-cf8d-48d3-86b3-3675c90f4c3b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_16924b9b-d656-4957-8c75-96436ea4fac3" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_eb6dca1f-ed2e-4bbb-9ece-4edc2cc53d84" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_98dbbe33-cf8d-48d3-86b3-3675c90f4c3b" xlink:to="loc_us-gaap_OperatingIncomeLoss_eb6dca1f-ed2e-4bbb-9ece-4edc2cc53d84" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_80bb6d23-22b3-4ade-975f-4c1431327353" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_98dbbe33-cf8d-48d3-86b3-3675c90f4c3b" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_80bb6d23-22b3-4ade-975f-4c1431327353" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_80bb6d23-22b3-4ade-975f-4c1431327353" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525" xlink:to="loc_us-gaap_SegmentDomain_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_36b5162b-e810-4532-ba3a-b28827c9cd92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d1e5f39f-9bf1-4a41-9d1b-8a32d5ed2525" xlink:to="loc_us-gaap_SegmentDomain_36b5162b-e810-4532-ba3a-b28827c9cd92" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_WoodProductsMember_eecb6203-9544-4888-b888-982351985ef5" xlink:href="bcc-20220630.xsd#bcc_WoodProductsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_36b5162b-e810-4532-ba3a-b28827c9cd92" xlink:to="loc_bcc_WoodProductsMember_eecb6203-9544-4888-b888-982351985ef5" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_bcc_BuildingMaterialsDistributionMember_4cf6d4df-20fb-4c62-869c-bee7cc780f92" xlink:href="bcc-20220630.xsd#bcc_BuildingMaterialsDistributionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_36b5162b-e810-4532-ba3a-b28827c9cd92" xlink:to="loc_bcc_BuildingMaterialsDistributionMember_4cf6d4df-20fb-4c62-869c-bee7cc780f92" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_55ee175c-7cb4-4492-b37e-7f55233199c5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_80bb6d23-22b3-4ade-975f-4c1431327353" xlink:to="loc_srt_ConsolidationItemsAxis_55ee175c-7cb4-4492-b37e-7f55233199c5" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_55ee175c-7cb4-4492-b37e-7f55233199c5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_55ee175c-7cb4-4492-b37e-7f55233199c5" xlink:to="loc_srt_ConsolidationItemsDomain_55ee175c-7cb4-4492-b37e-7f55233199c5_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_60aef99b-80e7-40e3-8191-b4daf235a2d7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_55ee175c-7cb4-4492-b37e-7f55233199c5" xlink:to="loc_srt_ConsolidationItemsDomain_60aef99b-80e7-40e3-8191-b4daf235a2d7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_b6cf23f0-01a8-4e07-be7c-7f29204f50be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_60aef99b-80e7-40e3-8191-b4daf235a2d7" xlink:to="loc_us-gaap_OperatingSegmentsMember_b6cf23f0-01a8-4e07-be7c-7f29204f50be" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_dcd4212f-ee1a-40c9-b63f-412c8ef11050" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_60aef99b-80e7-40e3-8191-b4daf235a2d7" xlink:to="loc_us-gaap_IntersegmentEliminationMember_dcd4212f-ee1a-40c9-b63f-412c8ef11050" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_81b33b81-c90d-4ed0-bb08-c0b8d17dc716" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateNonSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_60aef99b-80e7-40e3-8191-b4daf235a2d7" xlink:to="loc_us-gaap_CorporateNonSegmentMember_81b33b81-c90d-4ed0-bb08-c0b8d17dc716" xlink:type="arc" order="2"/>
</link:definitionLink>
</link:linkbase>

Top
Filing Submission 0001328581-22-000082   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)

Copyright © 2024 Fran Finnegan & Company LLC – All Rights Reserved.
AboutPrivacyRedactionsHelp — Mon., May 13, 3:49:11.1pm ET