One-armed bandit

A slot machine (American English), informally fruit machine (British English), puggy (Scottish English slang),the slots (Canadian and American English), poker machine (or pokies in slang) (Australian English and New Zealand English) or simply slot (American English), is a casino gambling machine with three or more reels which spin when a button is pushed. Slot machines are also known as one-armed bandits because they were originally operated by one lever on the side of the machine as distinct from a button on the front panel, and because of their ability to leave the player in debt and impoverished. Many modern machines are still equipped with a legacy lever in addition to the button.

Slot machines include a currency detector that validates the money inserted to play. The machine pays off according to patterns of symbols visible on the front of the machine when it stops. Modern computer technology has resulted in variations on the slot machine concept. Slot machines are the most popular gambling method in casinos and constitute about 70 percent of the average US casino's income.

The "slot machine" term derives from the slots on the machine for inserting and retrieving coins. "Fruit machine" comes from the traditional fruit images on the spinning reels, such as lemons and cherries.

Sittman and Pitt of Brooklyn, New York, U.S. developed a gambling machine in 1891 which was a precursor to the modern slot machine. It contained five drums holding a total of 50 card faces and was based on poker. This machine proved extremely popular and soon many bars in the city had one or more of the machines. Players would insert a nickel and pull a lever, which would spin the drums and the cards they held, the player hoping for a good poker hand. There was no direct payout mechanism, so a pair of kings might get the player a free beer, whereas a royal flush could pay out cigars or drinks, the prizes wholly dependent on what was on offer at the local establishment. To make the odds better for the house, two cards were typically removed from the deck: the ten of spades and the jack of hearts, which doubles the odds against winning a royal flush. The drums could also be rearranged to further reduce a player's chance of winning.

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