A slot is a narrow depression, groove, notch, or slit, especially one for receiving something, as a coin or a letter. It also refers to a position or period within a schedule, plan, or sequence: I can slots you in at 2 p.m.

In electronics, a slot can refer to any of several interfaces on a motherboard: an expansion slot that accepts ISA, PCI, or AGP cards; a memory slot; or an empty socket into which a removable chip can be inserted (see the picture below). The term is also used for any type of opening in a surface, such as the grooves or notches in the primary wings of certain birds that assist with the flow of air over their feathers during flight.

A number of features of online slot games increase their intensity and present a greater risk to players. The Commission has therefore sought to reduce these risks by introducing new measures for online slot machines, such as deposit and session limits, and banning reverse withdrawal functions. In addition, it is requiring that more prominent warnings are displayed for these games and that more information about their addictive nature is made available to consumers. Psychologists have found that people who play slot machines reach debilitating levels of gambling involvement three times more rapidly than those who play other types of casino games. This has led to calls for more regulation of these machines, including prohibition outside casinos and other licensed gambling establishments.