A slit or narrow opening, especially one for receiving something such as a coin or letter. Also used informally as a position or place. I walked past the poker tables and went straight to the slots.

A machine that pays out winnings according to a pattern of symbols on its reels, usually bars, diamonds, hearts, horseshoes, or liberty bells. Charles Fey’s invention of the slot machine in 1887 was a dramatic improvement over the older gambling machines, which required a lever to spin the reels and allow payouts. The newer devices were more reliable and faster than their older cousins, and were a big hit with the public.

In computing, a space on a disk or in memory that is reserved for a particular type of data. A program may be assigned up to a maximum number of slots in its environment, and the allocations are dynamically managed as programs run. Unlike the conventional hard disk drives, which use rotating platters to store data, solid-state memory uses semiconductor chips to store and retrieve information.

In aviation, an allocated time for a scheduled aircraft’s departure or arrival at an airport’s runway. Air traffic controllers assign slots to avoid repeated delays caused by too many flights trying to take off or land at the same time. In some cases, the capacity needed for a job to complete is temporarily shifted from one of the slots in which it is currently running. This is referred to as “slot borrowing”.