A slot is an area of a web page that can contain HTML markup. It can be either a regular div> or a shadow root. If a slot> is placed inside of a template>, the content for that named slot gets replaced with the template’s default value from the shadow root.

A slot can also refer to:

Usually, a slot is a game in which the player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode that’s validated when the machine is activated by a lever or button (either physical or on a touchscreen). The reels then spin and stop to rearrange symbols. When a winning combination appears, the player earns credits based on the pay table. Symbols vary by machine but classics include fruit, bells, and stylized lucky sevens. Some slots have multiple pay lines; others have one.