A slot is a narrow notch or groove, especially one for receiving something, as a key in a lock or a coin in a machine. A slot can also be a position in a group, series, or sequence. The word is probably from Middle Low German slit, and may be related to Old High German schot, Dutch schlot, and Middle High German schatz.

The appeal of slot machines is often attributed to their speed and ease of use. Players do not have to wait long to find out whether they have won or lost, and monetary gains are often accompanied by attention-grabbing music and amusing animations. Psychologists have also found that slot machine sounds can manipulate players’ responses to the game by making them overestimate their winnings and underestimate their losses.

A slot is also a term used in airport coordination to describe an authorization to take off or land on a specific day during a specified time period. The slots system is widely used around the world to manage air traffic, particularly at extremely busy airports where repeated delays would otherwise occur due to too many flights trying to take off or land at the same time.