A slot is a narrow depression, groove, notch, or slit, especially one that admits something, such as a coin or a letter. It is also a grammatical term for a morpheme position that can fit in a larger construction; compare filler (def 2).
The history of slot machines began in the 19th century with a New York company named Sittman and Pitt, who created a machine that paid out winnings by lining up poker hands. This machine was followed by another invention from Charles Fey, a mechanic and inventor, who replaced the poker symbols with diamonds, spades, horseshoes, hearts, and Liberty bells, and allowed players to place bets on multiple paylines. His machine was a hit, and it paved the way for modern slot machines.
In modern casinos, many people play slots with a computer program that generates random numbers every millisecond. The software controls how often the machine pays out, so there is no reason that it should be ‘looser’ or ‘tighter’ than another. Some manufacturers create different styles of machines that work on the same basic principles, but are based around themes such as television shows or movie titles.
In addition, the game’s pay tables provide information on all of the symbols and their possible combinations during gameplay. These are displayed on the screen alongside coin amounts and multipliers that can be won if the symbols line up in horizontal, vertical, diagonal, or zigzag patterns. Usually, these pay tables are accessed through a ‘help’ button or ‘i’ on the machine’s touch screens.