What is buck short for?

A buck is a commonly used slang term for a U.S. dollar. The origins of the term "buck" to refer to a dollar are not definitively known, but it is believed to have originated in the mid-19th century in the U.S. frontier when deerskin was a common medium of exchange. A deerskin was worth a dollar, hence the connection between "buck" and dollar.

Today, the term "buck" is used colloquially to refer to a dollar or money in general. It is often used in phrases like "bucks" (meaning dollars) or "big bucks" (meaning lots of money). The term can also be used as a verb to mean paying for something, such as "bucking up" for a meal or concert ticket.