tre·ble¹ / ˈtrebəl/ • adj. consisting of three parts; threefold: the fish were caught with large treble hooks dragged through the water. ∎  multiplied or occurring three times: she turned back to make a double and treble check.• three times as much or as many: the tip was at least treble what she would normally have given.• n. a threefold quantity or thing, in particular: ∎  (in show jumping) a fence consisting of three elements. ∎  a drink of liquor of three times the standard measure.• pron. a number or amount that is three times as large as a contrasting or usual number or amount: by virtue of having paid treble, he had a double room to himself.• v. make or become three times as large or numerous: [tr.] rents were doubled and probably trebled | [intr.] his salary has trebled in a couple of years. tre·ble² • n. a high-pitched voice, esp. a boy's singing voice. ∎  a boy or girl with such a singing voice. ∎  a part written for a high voice or an instrument of a high pitch. ∎  [as adj.] denoting a relatively high-pitched member of a family of similar instruments: a treble viol. ∎  (also treble bell) the smallest and highest-pitched bell of a set. ∎  the high-frequency output of an audio system or radio, corresponding to the treble in music.

treble.
1. Highest v. in choral singing, term today usually being applied to children, adult equivalent being soprano.

2. Upper part of comp., opposite in pitch of bass.

3. Applied as adjective to certain high-pitched instr. e.g. treble recorder, treble viol.

treble threefold, triple XIV; sb. quantity 3 times as great as another XV; (mus.) highest or upper part in a harmonized composition, soprano XIV. — OF. — L. triplus TRIPLE. The development of the mus. use is obscure.