A slot is a narrow opening, especially one for receiving or admitting something: a mail slot; a TV show’s eight-o’clock slot on Thursdays. It is also a position, as in a schedule or sequence: Her ideas fit neatly into the theory. To put or move something into a slot: He slotted the CD into the player.

A gambling machine that accepts cash or, in the case of “ticket-in, ticket-out” machines, paper tickets displaying barcodes. The slots spin and rearrange symbols according to a paytable, and if they line up in a winning combination, the player earns credits based on that table. In some cases, the slot may allow the player to enter a bonus level or jackpot level.

In airport coordination, a block of time in which a scheduled flight can take off or land at an airport on a given day during a specified period. The concept of slots is a major factor in air traffic control and helps prevent repeated aircraft delays caused by too many flights trying to take off or land at the same time.

Unlike the Sittman and Pitt invention, Charles Fey’s slot allowed automatic payouts, had three reels, and used symbols like hearts, spades, horseshoes, diamonds, and liberty bells (the third aligning Liberty Bell was the highest win). These changes led to an enormous increase in popularity for the new machine, which is still a casino favorite today. In online slots, players can find video results for the games they are interested in. They can also see the payback percentages that the games were designed to return, although these percentages will often vary by jurisdiction.