A narrow notch or groove, as in a keyway or slit, or the opening of a window, door, or machine. The slots on the wings of certain birds provide a vent for smooth airflow during flight. A position, time, or place occupied by an individual or an airplane, as authorized by an airport or air-traffic control authority: Airplanes have to wait for their slot before they can take off.

A casino’s rotating mechanical device that dispenses tickets or cash to customers who have earned the right to play a game, usually with a pull on a lever or handle. Modern slot machines are computerized and have many more features than the old three-reel mechanical ones.

One of the biggest mistakes gamblers make is relying on “theories” about how slots work. For example, some players believe that moving to another machine after a short period of time or after seeing a player win a large amount will increase their chances of hitting. In my 20 years of working with, on & around slot machines I have found this to be a foolish belief. Every spin of a slot machine is random and previous results have no bearing on future outcomes.

The first slot machine was invented in 1887 by Charles Fey, who added three reels and replaced the poker symbols with diamonds, spades, horseshoes, hearts & liberty bells, making it easier to win by aligning three of the same symbols on a pay line. His design also allowed automatic payouts.