A slot is a position in a group, series, or sequence. It is also a place in a line up or in a piece of machinery.
The word is also used in gambling as a symbol for a machine that pays out winnings (or tries to). Many slot machines are themed, and their symbols or bonus features align with the theme. Slots are operated by pulling a lever or button, or pressing a touchscreen on a tablet computer, to spin and stop the reels. The reels are then rearranged to display different symbols, and the player wins credits based on those symbols according to the pay table.
Some people try to take advantage of the randomness of slot machines by using strategies like moving on to a new machine after a set number of bets, or trying to figure out how much a machine is likely to pay out based on its history of payouts (under the assumption that it will loosen up after a while and become more likely to win). However, these strategies are useless, as every spin is completely random.
The term is also sometimes used to refer to an expansion slot on a motherboard, particularly an ISA or PCI slot, although this usage is more common in the United States than in other countries, where the term is often reserved for memory slots. The usage is not consistent, however, and there are some other terms for these slots, including peripheral component interconnect and accelerated graphics port.