A narrow opening into which something can fit, such as the slot in a door or the time slot on a calendar. It can also refer to a position within a group, series, or sequence. The term was probably originally derived from the idea of a groove or channel in something, such as wood or metal, into which something could fit snugly, like a belt in its buckle or a book in its binding. The sense of a specific position is attested by 1916 (as in “the slot on the copy desk”) and 1937 (in reference to the position of a car seat belt).
In a slot machine, a player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode into a designated slot on the machine. The machine then activates a number of reels, each with multiple symbols, and the player earns credits based on the pay table. Symbols vary according to the theme of the game, but classic symbols include fruits, bells, and stylized lucky sevens.
A slot is a dynamic placeholder that waits for content (a passive slot) or is filled with content based on the action of a scenario or targeter (an active slot). A slot can hold one type of repository item, but it should not be used with multiple scenarios or targeters because they will interfere with each other. In ACC, slots are similar to renderers and can be added to a page using the Add Items to Slot action or the Targeter.