A narrow notch, groove or opening, as in a keyway in machinery or a slit for a coin in a vending machine. To slot something into another is to place it in the space where it fits, as in He slotted the CD into the player. The term is also used to describe a position in a group, series or sequence.

Slots are used at busy airports to prevent flights from overrunning each other’s airspace, leading to flight delays and unnecessary fuel burn. This is done by assigning each aircraft a time “slot”, which is an authorization to take off or land on a specific day and during a specific time period. The number of slots available at a given airport is limited to protect against repeated disruptions of aircraft operations, and they are only allocated to the first plane to arrive at the airport each day.

To play a slot, the player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode into a designated slot on the machine. The machine then activates a mechanism that spins the reels and, if the symbols line up in a winning combination, the player earns credits based on the paytable. Symbols vary from game to game, but classic symbols include fruits, bells and stylized lucky sevens. Most slot games have a theme, and the symbols and bonus features are typically aligned with that theme.

Most modern slot games are programmed using a random number generator (RNG) to produce a sequence of numbers that determines the outcome of each spin. Some players believe that certain patterns or combinations of numbers on the reels might help them predict when a big win will occur, but the RNG assures that each spin is a separate event and that the created numbers are not affected by previous outcomes or by numbers produced earlier.