Tremolo

n.

1.

(Mus.) The rapid reiteration of tones without any apparent cessation, so as to produce a tremulous effect.

Noun	1.	tremolo - (music) a tremulous effect produced by rapid repetition of a single tone or rapid alternation of two tones
	2.	tremolo - vocal vibrato especially an excessive or poorly controlled one

music, palpitation, quiver, quivering, shakiness, shaking, trembling, vibration