What Is a Slot?

A slot is a narrow opening in a machine or container. It is also a term used to refer to an allocated time or place for an aircraft to take off or land as authorized by the airport or air-traffic authority:

It’s been twenty years since central flow management was introduced in Europe, and the results have been huge savings in delays and fuel burn, as well as major environmental benefits.

In a slot machine, symbols line up on reels to create winning combinations. The machines are operated by inserting cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode. A button or lever (either physical or on a touchscreen) is then activated to spin the reels and stop them. When the reels stop, a random-number generator sets a number or numbers that correspond to symbols on different pay lines. The microprocessors inside modern slot machines make each possible combination appear to have equal chance of appearing on the screen, even though the odds of any particular symbol are much lower.

Charles Fey’s invention of a slot machine made them easier to win by allowing payouts when three or more matching symbols aligned on the payline appeared on one spin. Other machines were already in existence, but Fey’s allowed more frequent and higher wins than those of his competitors.

A slot can also refer to a position, assignment or job: She was given the slot of chief copy editor. The unmarked area on an ice hockey rink that allows players to gain a vantage point to attack the opposing team’s goal is sometimes called a “slot.” To slot something into a space or place means to put it where it belongs.