A slot is a narrow opening or groove, usually for receiving something, such as a coin or letter. Also called a slit, notch, or aperture. The slot of a window is wider than the sill. The wing of some birds has a small, pointed opening between the tips of its primaries, which is used to direct airflow over them during flight.

A type of slot machine that uses reels to display symbols and pay out credits when a winning combination lines up on the screen. Unlike traditional mechanical machines, modern slot machines are operated by microprocessors that vary the probability of a given symbol appearing on each reel and determine how much credit a player receives when it does appear. Depending on the theme of the slot game, some slots use symbols that represent popular characters or items, while others feature classic images such as fruits and stylized lucky sevens.

In computer engineering, a slot (also known as an expansion slot) is an engineered technique for adding capability to a system in the form of connection pinholes and a place to fit an expansion card containing the circuitry that provides some specialized functionality. Almost all desktop computers come with a set of expansion slots, allowing for future upgrades or add-ons to be installed without removing the motherboard and/or hard drive.

In business, slot-based scheduling can help teams prioritize work based on its urgent nature and/or important deadlines. This method of organization can improve productivity and efficiency by ensuring that team members have a clear understanding of their workflow and what needs to be accomplished by various dates and times.