A narrow depression, perforation, or opening, such as a slot in a door for a key or a hole for a coin in a vending machine. (also: slit, notch, or aperture; see also slit). A position in a group, series, or sequence; a time period in a schedule or program. I have booked a haircut at the 2 p.m. slot. The program received a new time slot on the broadcasting schedule.

A type of gambling machine that displays a series of reels and pays out winning combinations according to a paytable displayed on the machine. Invented by Charles Fey in 1899, the first slot machine had three spinning reels that lined up symbols to make poker hands. These machines became popular across the United States during the 1920s, when they were sometimes operated illegally in private social clubs. By the 1930s, however, knowledge of their distribution was widespread, and governments passed laws restricting their sale, transportation, and operation except in Nevada.

A container that displays dynamic content on a Web page, often in conjunction with a scenario. A slot can be passive, waiting for a call to add contents, or active, filling in a placeholder for its own contents based on a call from a scenario or a renderer. In a Web application, a slot can be replaced by a template that contains template v-slot:header> or a JavaScript function for dynamically adding a header to an element in the page.