A slot is a narrow opening in a machine or container, often used to receive coins. A slot can also be a time period in which something can take place, such as a scheduled appointment. A slot can be a position or location in a game of chance, such as the one where chips are placed to start playing blackjack. It can also refer to a specific casino game, as in the phrase “slot in” when talking about tactics that are employed in the game.

In casinos and other gaming establishments, slots are machines that accept cash or, on some older machines, paper tickets with a barcode that get scanned as the player inserts them. Players activate the machines by pushing a lever or button (either physical or on a touchscreen), which then spins the reels to rearrange the symbols. When the symbols line up in a winning combination, the player earns credits according to the pay table. The type and number of symbols on a slot machine vary, but classics include fruits, bells, and stylized lucky sevens. Many slot games have a theme, with bonus features aligned with that theme.

In aviation, a slot is a reserved space at an airport for a particular aircraft, either on the runway or in parking spaces. Air traffic management slots are also known as Flow Management Slots, and they are used when an airport is constrained, such as during peak hours. The use of a slot can result in significant savings in delay and fuel burn.