A slot is a narrow notch or opening, as in a keyway in machinery or a slit for a coin in a vending machine. It is also a position in a group, series, or sequence, such as a time slot on a calendar or a job opening.

In aviation, a slot is an authorization for an aircraft to take off or land at an airport at specific times, usually in response to air traffic control congestion (such as at Heathrow). A flight may not use its assigned slots without permission from the air traffic controller. Air traffic management systems often manage a set of slots for each runway at very busy airports.

In electromechanical slot machines, a “tilt” switch would make or break the circuit when a machine was tilted and prevent it from starting up. Modern video slot machines do not have such switches, but any kind of technical fault (door switch in the wrong state, reel motor failure, out of paper) is still referred to as a “tilt”.

A slot is also the name for the space in an ice hockey rink where a center or winger can shoot at a goal without being deflected, because it offers a straight-on view of the net. The slot is usually protected by defenders who skate around it, but a speed player can get through the defense to score. The term is also used for the corresponding area in an American football game, where a wide receiver can catch passes in front of the face-off circles.