A narrow notch, groove, or slit, especially one for receiving something, such as a coin or letter. Also a position in a series or sequence: Her TV show was slotted at eight o’clock.

During the 19th century, Charles Fey invented the modern slot machine, which is a casino game in which reels spin and symbols match to earn credits according to the paytable. The first machines used mechanical operations and a lever to activate the reels, but most modern slot machines use microprocessors to control the game. Depending on the theme, a machine may also have multiple screens and additional bonus features.

A place in a queue, or in a schedule or order of events: He waited in the second slot.

In aviation, a time slot allocated to an aircraft by an airport when it is constrained either by runway capacity or available parking space: The airline was able to land in the afternoon, but had to wait for a slot.

In computer science, a range in memory or on a disk in which a particular type of object can be stored: The program has four save slots. In Australian rules football and rugby, a way of scoring a goal: He slotted the ball between the posts. Also, in European air traffic management, the time when an airspace is allocated to an aircraft, preventing unnecessary delays and fuel burn: See also slot and congestion.