Slot is a narrow opening in a machine or container, for example the hole that you put coins into to make it work. A slot can also refer to a position in a schedule or program where an activity can take place. A football player who lines up close to the sidelines is often called a slot receiver because they create mismatches against linebackers and safeties.

Historically, slot machines were a popular form of gambling. They occupied many casinos and were operated by independent operators who had to compete with each other for customers. Unlike other casino games, slot machines do not require players to bet large sums of money in order to win. The amount of money a machine pays out depends on the symbols it displays and how often they appear on the pay line. The pay table is printed on the face of the machine or in a help menu.

When airlines are faced with congestion problems at an airport, they can purchase a slots from EUROCONTROL to fly into a restricted zone when demand is high. These slots can be used to avoid costly delays, which reduces fuel burn and environmental impact.

In computer science, a slot is a function that can be invoked by any component using a signal-slot connection. This allows functions to encapsulate reusable logic and visual output, delegating the latter to other components via scoped slots. This is similar to how lambda functions work in a functional programming language.