A slot is a narrow depression, groove, notch, or aperture, especially one elongated and deep enough to accommodate something such as a coin or letter. It may also refer to:

In casino gaming, a slot is an area on the machine that pays out credits according to a pay table. The pay table is a list of winning combinations and their payout amounts. The symbols on the pay table must line up with those on the reels to make a winning combination. Some slots also feature a Wild symbol, which can substitute for other symbols to complete winning lines.

The first slot machines were invented in the 19th century, and their popularity grew rapidly. By the 1920s, they were commonplace in many casinos. However, forces of morality and the clergy often opposed their use, and they were eventually banned in cities such as San Francisco.

With the advent of electromechanical slot machines, manufacturers could vary their payouts depending on which symbols appeared more frequently on each reel. Manufacturers also began to collect data on player habits, which helped them develop a variety of games with different themes and designs to appeal to various audiences.

In aviation, a slot is an authorization to take off or land at a particular airport during a specified time period. Air traffic controllers issue slots to help manage the flow of aircraft at busy airports and avoid repeated delays caused by too many flights attempting to take off or land simultaneously.