A narrow notch or groove, as in a keyway in machinery or a slit for coins in a vending machine. Also: a position in a group, series, sequence, etc.

A slot is a dynamic placeholder that either waits for content (a passive slot) or calls out to get it (an active slot). A slot works in tandem with scenarios and renderers to deliver dynamic items on a Web page. A slot is designed to hold one type of content only; combining different types of content in the same slot can lead to unpredictable results.

An arrangement of symbols on a reel that must appear in a particular pattern to award a payout. A slot can have more than one payline per spin, and the amount awarded depends on how many matching symbols appear and which bet size was used. Most slot machines have a specific theme and feature symbols that align with the theme.

Sports A second screen bonus round in a video game that allows players to open packages and collect payouts. The bonus rounds vary in complexity from one game to the next and are often themed after the main game or character. A popular example is the WMS Gaming “Jackpot Party” slot, in which players touch packages to reveal prizes until they hit a ‘pooper’ symbol, which ends the bonus round.

The name for a time slot reserved for an aircraft to land or take off at a busy airport, which helps prevent flight delays by controlling the number of planes attempting to land or take off during limited time periods. The use of slots is a common strategy in air traffic management worldwide to reduce congestion at congested airports and other busy sites.