What Is a Slot?



A slit or other narrow opening, especially one for receiving something, such as coins or letters. Also: a position or time in a series or sequence, especially one that can be filled; an assignment or job opportunity.

In a slot machine, players insert cash or, in “ticket-in, ticket-out” machines, paper tickets with barcodes, into a slot and activate the machine by pushing a lever or button (either physical or on a touchscreen). The reels spin and stop to rearrange the symbols. When the winning combination appears, the player earns credits. In some games, the symbols must match on a specific pay line to win. The pay table, which lists the payouts for each symbol, is displayed on the screen in addition to the reels and is typically above or below them.

The number of possible combinations of symbols on a slot’s reels, or stops, is limited by the number of positions for each symbol, the number of paylines, and the maximum bet size. But the number of combinations isn’t the only factor that influences winnings: Different symbols have different probabilities of appearing. In electromechanical machines, this difference was reflected by the fact that some symbols occupied only one of several slots on a reel, while others occupied multiple. But microprocessors in modern slot machines allow manufacturers to weight certain symbols more than others.

In aviation, a “slot” is the authorization to operate at a constrained airport at a specific time during a particular day, or for air traffic management purposes. Slots are used to avoid repeated congestion at busy airports and can be traded or held as valuable assets.