In vocal music, the most common category of male voice, between the bass and the tenor .
Its range is approximately from the second A below middle C to the F above middle C. The term baritonus was first employed in 15th-century five-and six-voice part music; when four-part settings became standard, the baritone part was dropped, and natural baritones were forced to develop either their bass or tenor register. Instruments that play principally in the baritone register include the baritone saxophone and the baritone horn.