The slot machine or one-armed bandit is a gambling device that, when a coin is dropped into its slot and its handle pulled down, activates three or more horizontal reels marked with various symbols such as stars, card suits, numbers, fruit (especially plums, cherries, lemons, oranges, and watermelons), or the word jackpot. The operator receives a payoff if, when the reels come to rest, matching symbols are shown in the display windows; the amount of the payoff may range from several coins to all of the coins in the machine, depending on how the symbols line up. The slot machine pays the winner by dropping coins into a cup or trough.

The first slot machines, which appeared in the United States toward the end of the nineteenth century, were novelty devices usually found in taverns. They did not reward users...