A narrow notch, groove or opening, as a keyway in machinery or a slit for a coin in a vending machine. Also: (in Australian rules football and rugby) To kick a ball between the posts for a goal.

In computer hardware, a slot is an interface for adding expansion capabilities to a motherboard. The slots are usually closely-spaced pinholes in the motherboard that can accommodate an expansion card with circuitry for adding new capability such as video acceleration, sound support, or disk drive control. The term “slot” is also used to refer to a specific kind of expansion port on a desktop or notebook computer, such as an ISA or PCI slot.

In a slot machine, the player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode into a slot on the machine. The machine then activates the reels, which spin and stop to rearrange symbols. If the symbols line up in a winning combination, the player earns credits according to the paytable. Depending on the game, the symbols can vary from classic objects such as fruits and bells to stylized lucky sevens. Many slot games have a theme, and the symbols and bonus features are aligned with that theme.

Psychologists have found that people who play video slot machines can reach a debilitating level of gambling addiction three times faster than those who play traditional casino games. Because of this, players should always be aware of their own limits and stay within them. Abuse of a machine can result in the machine shutting down and voiding any remaining credits. It is also not advisable to slam or jiggle the machine, as this can cause damage. Modern slot machines are armor-plated and have tempered glass, and they are tested against abuse before they leave the factory, including being zapped with a Tazer.