hyperbolaeon

1. (music) The highest tetrachord.Examples: "Trite, the third; as, Trite Hyperbolaeon, the third string, reckoning from the top of the hyperbolaeon or highest tetrachord; […]"; "1914, Vitruvius (translated by Morris Hicky Morgan), Ten Books on Architecture In the middle range, place first at the extreme ends the vessels which give the note of the chromatic hyperbolaeon; next to them, those which give the chromatic diezeugmenon, a fourth below; third, the chromatic synhemmenon; fourth, the chromatic meson, a fourth below; fifth, the chromatic hypaton, a fourth below; sixth, the paramese, for this is both the concord of the fifth to the chromatic hyperbolaeon, and the concord of the chro­matic synhemmenon."