Conversation so far:
where did the buck stops here come from
The buck stops here was popularized by US president Harry Truman. The phrase is based on the metaphorical expression passing the buck, that came to mean passing blame.
where did buck passing come from
Passing the buck originated from a ritual practiced during card games. Card players used to place a marker, called a buck, in front of the person who was the dealer.
what is another definition of buck besides being the name of a marker for the person who was the dealer in card games
A buck is the male of some horned animals, especially the fallow deer, roe deer, reindeer, and antelopes.

Question: why is the word used for dollars
Self-contained rewrite: why is the word buck used for dollars