Dead Key

A dead key is a special kind of a modifier key on a typewriter or computer keyboard that is typically used to attach a specific diacritic to a base letter. The dead key does not generate a (complete) character by itself but modifies the character generated by the key struck immediately after. Thus, a dedicated key is not needed for each possible combination of a diacritic and a letter, but rather only one dead key for each diacritic is needed, in addition to the normal base letter keys.

For example, if a keyboard has a dead key for the grave accent (`), the French character à can be generated by first pressing ` and then A, whereas è can be generated by first pressing ` and then E. Usually, the diacritic in an isolated form can be generated with the dead key followed by space, so a plain grave accent can be typed by pressing ` and then Space.