How did the word buck come to...

This American slang word for a dollar may have its origins in animal skins that were classified as “bucks” and “does.” The bucks, larger and more valuable than the does, could have become part of early American business terminology (around 1800) and later slang for a dollar. This usage also may have come from the game of poker. During the game’s heyday (the late 19th century), a marker called a buck was placed next to a poker player to remind him that it was his turn to deal next. A silver dollar was sometimes used as the marker, perhaps leading to the expression.