A slot (plural slots) is an opening or position. In a computer, a slot is one of the places where you can put an expansion card that provides specialized capability, such as video acceleration or disk drive control. Most desktop computers come with a number of slots.
A small amount of money paid to keep a player seated and betting during long periods of time, often in the hope that their luck will change. A slot is typically referred to as hot when it pays out winning combinations frequently, but is considered cold if it has not paid out at all for several spins.
In casino games, the term slot refers to a combination of paylines and a special symbol that can trigger bonus rounds or free spins. Some slots allow players to choose which paylines they wish to bet on, while others automatically wager on all available lines. Players can find a list of paylines and winning combinations in the game rules.
A slit or narrow opening, especially one for receiving something, as a coin or a letter. Also called a slot hole, slot, aperture, or window. (American Heritage Dictionary of the English Language, Fifth Edition)