A slit or narrow opening, especially one that allows passage of something.

Also known as a slot machine or fruit machine.
A computer-controlled device that randomly assigns a sequence of numbers to symbols on a reel to determine whether or not a spin is a winning one. A slot machine can accept cash or, on some machines, a paper ticket with a barcode that the player inserts into a reader at the side of the machine to activate the spinning reels. The pay table on a slot machine displays the payout values and symbols that can land in a winning combination along with any bonus features for that game.

Often, the payout value and symbol combinations on a slot machine are aligned with its overall theme. In addition, most slot games have a specific number of paylines, which are identified by a pattern or series of symbols, such as the traditional fruit symbols or stylized lucky sevens.

A slot is a dynamic placeholder that either waits for content (a passive slot) or can be called by a scenario using the Add Items to Slot action or by a targeter. Slots are used with scenarios to manage the dynamic items that appear on a Web page. Using slots and scenarios together is the foundation of building Web components. For more information on using these elements, see the article Using Scenarios and Slots.