A slot is a narrow opening or groove, typically used to hold a piece of hardware. A slot in a schedule or program is a time when an activity can take place.
A “slot” is also the name for a position or job, such as chief copy editor.
On a slot machine, players insert cash or paper tickets with barcodes into a designated slot, activate a lever or button (physical or virtual), and spin reels that rearrange symbols. A winning combination earns credits based on the paytable. Typical symbols include fruits, bells, and stylized lucky sevens. Most slot games have a theme, and bonus features align with that theme.
Before the 1980s, most slot machines only had one payline and allowed only a few dozen combinations. This limited jackpot sizes and made it difficult to estimate when a player was due for a win. Manufacturers solved this problem by adding electronics that weighted particular symbols. This made the appearance of losing symbols on the display less frequent than their frequency on the physical reels, but it still prevented players from predicting when they would hit. Some players prefer this change, while others object to it because they feel that increased hold decreases their average time on machine. In either case, the change has prompted discussion about whether or not it is ethical to increase a slot’s hold percentage.