1640s, from Italian trillio, triglio "a quavering or warbling in singing," probably of imitative origin. The verb is 1660s, from Italian trillare "to quaver, trill." Related: Trilled; trilling.
in phonetics, a vibration or series of flaps (see flap) of the tongue, lips, or uvula against some other part of the mouth. The Spanish rr in perro ("dog") is a tongue trill, and the French r is sometimes pronounced as an uvular trill