The slang "buck" or "bucks" when referring to money is so common-place that no-one really questions its oddity. But it turns out that the word "buck" is short for "buck-skin" (from a deer). Buck-skins were used as currency once upon a time.

The Indians taught the European settlers the value of a buck. In the eighteenth century, that meant a deerskin, used for trading in its own right and as a unit of value for trading anything else. So in 1748, while in Indian territory on a visit to the Ohio, Conrad Weiser wrote in his journal, "He has been robbed of the value of 300 Bucks"; and later, "Every cask of Whiskey shall be sold...for 5 Bucks in your town."

In the next century, with deerskins less often serving as a medium of exchange, the buck passed to the dollar. A Sacramento, California, newspaper reported this court judgment in 1856: "Bernard, assault and battery upon Wm. Croft, mulcted in the sum of twenty bucks."

Inflation has hit buck in the later twentieth century, so that in big-bucks transactions buck can mean one hundred or even one hundred thousand dollars. But sometimes a buck is still just a buck.