Compose key

A compose key, also called multi key, is a part of the computer keyboard that is—or behaves like—a kind of special dead key. Thus, unlike a modifier key, which must be held down, the compose key can be released before the following key stroke. The effect of the compose key is to convert to a dead key every specified key that is pressed after it. The next (or even a later) keypress triggers the insertion of an alternate character, typically a precomposed character or a symbol.