When did the dollar bill become a "buck"? Why is it called that anyway?

Answer 1

BUCK

Meaning -(1) A dollar.
(2) An amount of money: working overtime to make an extra buck.

It is not specifically for Dollar bill alone, any currency can be refered with the term BUCL-
Origin: 1748

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.

Passing the buck is a different matter. In the late nineteenth century, poker players designated the dealer with a marker they called the buck, apparently so named because it was often a knife with a handle made of buckhorn. When responsibility for dealing changed to the next player, they passed the buck.

Answer 2

The word buck— possibly an abbreviation of buckskin or buckarooney, an intrinsic "currency" for trade with American Indians known since 1746 — has been recorded since 1856 and is widely used as a synonym for the dollars of many countries, including Australia, Canada, New Zealand, Hong Kong and the United States.
Greenback, a nickname originally applied to a 19th-century United States Demand Note, is now a common specific reference to the U.S. dollar. It is not used for coins or dollars of other countries, whose dollar bills are often not green.
"Dollar" is a now-obsolete British slang term for ten shillings.
The slang term "smacker" has its roots in the Yiddish word "schmako."

Answer 3

Definition Of Buck

Answer 4

Buck: Meaning of "dollar" is 1856, Amer.Eng., perhaps an abbreviation of buckskin, a unit of trade among Indians and Europeans in frontier days, attested in this sense from 1748.

- From http://www.etymonline.com/index.php?term=buck