A slot is a narrow, elongated depression, groove, notch, slit, or aperture, especially one for receiving or admitting something, such as a coin or a letter. It may also refer to a position in a sequence or series: The program received a new time slot on the broadcasting schedule. See also hole (def 1 ), window, vacancy, and niche. A slot can also be a position in a machine or an aircraft: The pilot’s seat is in the right-hand side of the cockpit.

A mechanical slot machine is a gambling device that pays out winnings when its reels stop rotating after a spin. A player inserts cash or, in ticket-in, ticket-out machines, a paper ticket with a barcode, into the slot and activates it by pushing a button or lever. The reels then spin and stop to rearrange the symbols, and the player receives credits based on the paytable. Most slot games have a theme, with traditional symbols such as fruits, bells, and stylized lucky sevens.

Modern electromechanical slot machines are designed to be cheat-proof. A variety of sensors monitor the state of the machine, and if any malfunction is detected—for example, a door switch in the wrong position, an out-of-paper indicator, or a tilt sensor—the machine is programmed to reset and restart. Some machines have a jackpot level that grows over time as players place coins into them; others have random number generators that produce completely random results every millisecond.

Online slot is a type of casino game that allows players to bet virtual coins on a variety of themes and paylines. These games often have wilds that can substitute for other symbols to increase a player’s chances of winning. They are available from many websites and mobile apps. Some slots are progressive, meaning they accumulate a joint jackpot over time, while others have a fixed jackpot amount.

There are two types of slot: Class 2 and Class 3 machines. Class 2 slots use a predetermined series of outcomes in a random order, while class 3 slot machines have random number generators that produce a random set of outcomes each millisecond. Class 3 machines are more reliable than class 2 slots, but they don’t offer the same jackpot levels or other bonus features as class 2 machines do.

The word slot can also refer to the elongated depression in a computer motherboard where an expansion card is installed. Various expansion cards, such as those for sound, video, or network, are often referred to as slots. Similarly, the term “slot” can also describe the location on a computer where a memory module is installed. Some computers have a removable tray that can hold multiple memory modules. Other computers have dedicated slots for each memory module. In both cases, the slots can be configured for different sizes of RAM, allowing for more or less than the maximum capacity allowed by the motherboard. A slot can also be used to connect a computer to a monitor, printer, or other peripheral devices.