vibrato Look up vibrato at
1861 (adv.), 1870 (n.), "tremulous effect in music," from Italian vibrato, from Latin vibratus, past participle of vibrare "to vibrate" (see vibrate).
Strictly, the vibrato is distinct from the tremolo, in that the latter involves a perceptible variation in pitch; but in common usage the terms are made synonymous. [Century Dictionary]