A slot is a narrow aperture or groove. It may refer to:

A machine where people can place money, a coin, or paper tickets with barcodes in order to win credits based on a paytable. These machines are usually themed, with symbols aligned to that theme. The machine will then spin the reels to rearrange the symbols and give the player a payout if the winning combinations appear on the pay line. Depending on the game, the payout can be large or small.

Modern slot machines have microprocessors inside that control how each spin is played. This allows manufacturers to weight particular symbols, giving them a higher probability of appearing on the payline than they would have had on a mechanical reel. The computer also uses step motors that use short, digital pulses to move the reels. This allows the motor to stop precisely at a predetermined position, rather than having the uncertainty that causes an ordinary electric motor to slow and stop suddenly.

Some players believe that a machine that has gone a long time without paying off is “due” to hit. While it is true that some machines are more likely to pay out than others, this belief is based on false assumptions. If a machine has been out of action for awhile, the chances that it will hit are no greater than those of any other machine in the casino. In fact, some casinos deliberately keep hot machines at the ends of aisles because they are more likely to draw attention.