A croupier or dealer is someone appointed at a gambling table to assist in the conduct of the game, especially in the distribution of bets and payouts. Croupiers are typically employed by casinos. Originally a "croupier" meant one who stood behind a gambler, with extra reserves of cash to back him up during a gambling session. The word derived from croupe (the rump of a horse) and was by way of analogy to one who rode behind on horseback. It later came to refer to one who was employed to collect money from a gaming table.

Source: Wikipedia