A slot is an opening in a computer where you can insert a printed circuit board. A slot is also known as an expansion slot because it allows you to add capabilities to a computer. Slots are not to be confused with bays, which are sites within a computer where you can install disk drives.

A “slot” can also refer to a place where a player places coins or paper tickets with barcodes in a slot machine in order to activate the spinning reels and determine the outcome of the game. Many slot games have a theme, and symbols and bonus events can be aligned to that theme. A slot can be played in a live casino or online, and the game’s theme may be reflected in its visual design and sounds.

In a slot machine, a near miss occurs when feedback for a loss approximates a win. For example, receiving the combination of cherries-cherry-lemons on a fruit machine is visually similar to winning three cherry free throws in basketball. This illusion seems to exploit learning processes, most notably conditional reinforcement, which evolved to detect contingent (i.e., non-random) outcomes. However, the empirical evidence on this near-miss effect is inconclusive, and there are alternative explanations for the result.