The range of a voice or instrument. This use of the term arose because of its old meaning of all the notes found on the Guidonian hand. In Medieval theory, the gamut is the note G on the bottom line of the bass clef.The key of G.The range of notes available in Guido of Arezzo's hexachordal system, from the low G an octave and a fourth below middle C (known as "gamma ut," hence the term "gamut") to E an octave and a third above middle C. See hexachord.