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

A slot in a schedule or program is a place where an activity can take place. The visitors can book their slot a week or more in advance.

In casinos, a slot is a space for the spinning of reels and payout of winnings. There are a number of different types of slots, each with its own unique symbols and gameplay. Some have a fixed number of pay lines, while others allow players to select the number of paylines they want to activate before playing.

There is no strategy involved in playing slots, which makes them a good choice for people who want to gamble without having to think too much. However, some states (such as Alaska, Arizona, Arkansas, Kentucky, Minnesota, Montana, New Hampshire, Rhode Island, Tennessee, and West Virginia) prohibit private ownership of slot machines or limit them to those of a certain age.

In aviation, a time slot is an authorization to take off or land at an airport on a specific day during a specified period of time. The use of slots helps to manage air traffic at busy airports and prevent repeated delays. A slot may be assigned to a single aircraft or to multiple aircraft in a queue. In addition to built-in slot types such as amount, duration, and number, custom slot types can be defined to map to different entities in an utterance.