(1) The upper end of the audio spectrum, usually given to be about 2kHz-20kHz. (2) A high voice or musical part equivalent to soprano, particularly a part sung by a boy. By extension, instruments which operate in a similar range may be prefixed by the term, e.g., treble recorder. The treble, or G, clef is the one with middle-C one leger line below the stave. See also alto, baritone, bass, and tenor.