Webster's Revised Unabridged Dictionary · 1913

Treble

Treble , adjective

[Old English treble threefold, Old French treble, treible, Latin triplus. See Triple.]

1.
Threefold; triple.
A lofty tower, and strong on every side With treble walls. — Dryden
2.
(a) (Music) Acute; sharp; as, a treble sound.
(b)
(Music) Playing or singing the highest part or most acute sounds; playing or singing the treble; as, a treble violin or voice. — Bacon

Treble , adverb

Trebly; triply. [Obsolete] — J. Fletcher

Treble , noun

[“ It has been said to be a corruption of triplum [Lat.], a third part, superadded to the altus and bassus (high and low).” Grove.]

(Music) The highest of the four principal parts in music; the part usually sung by boys or women; soprano.
It has been said to be a corruption of triplum [Lat.], a third part, superadded to the altus and bassus (high and low). — Grove

This is sometimes called the first treble, to distinguish it from the second treble, or alto, which is sung by lower female voices.

Treble , transitive verb

1.
To make thrice as much; to make threefold.
Love trebled life. — Tennyson
2.
To utter in a treble key; to whine. [Obsolete]
He outrageously (When I accused him) trebled his reply. — Chapman

Treble , intransitive verb

To become threefold. — Swift