Sentence:  This , however , did not bar finding that du Pont had become pre-eminent as a supplier of automotive fabrics and finishes to General Motors ; that these products constituted a `` <WSD>line</WSD> of commerce '' within the meaning of the Clayton Act ; that General Motors ' share of the market for these products was substantial ; and that competition for this share of the market was endangered by the financial relationship between the two concerns : 
Meaning of the word marked with <WSD> tags:  the principal activity in your life that you do to earn money