Meaning

noun a note that alternates rapidly with another note a semitone above it

verb pronounce with a trill, of the phoneme `r'

noun the articulation of a consonant (especially the consonant `r') with a rapid flutter of the tongue against the palate or uvula

originProbably related to Old English þweran (“to twirl, stir”). Compare twirl, thirl, and Swedish trilla, Norwegian trille, etc.

Etymology from Wiktionary, CC BY-SA 3.0