Sentence:  Hercules L. Dousman , fur <WSD>trader</WSD> and merchant at Prairie du Chien , contracted to supply Selkirk 's people with some 300 head of cattle , and Alexis Bailly and Francois Labothe were hired as drovers . 
Meaning of the word marked with <WSD> tags:  someone who purchases and maintains an inventory of goods to be sold