flute | Etymology of flute by etymonline

early 14c., from Old French flaut, flaute (musical) "flute" (12c.), from Old Provençal flaut, which is of uncertain origin; perhaps imitative or from Latin flare "to blow" (according to Watkins, from PIE root *bhle- "to blow"); perhaps influenced by Provençal laut "lute." The other Germanic words (such as German flöte) are likewise borrowings from French.

Ancient flutes were direct, blown straight through a mouthpiece but held away from the player's mouth; the modern transverse or German flute developed 18c. The older style then sometimes were called flûte-a-bec (French, literally "flute with a beak"). The modern design and key system of the concert flute were perfected 1834 by Theobald Boehm. The architectural sense of "furrow in a pillar" (1650s) is from fancied resemblance to the inside of a flute split down the middle. Meaning "tall, slender wine glass" is from 1640s.