Tremolo \Tre"mo*lo\, n. [It. Cf. {Tremulous}.] (Mus.) (a) The rapid reiteration of tones without any apparent cessation, so as to produce a tremulous effect. (b) A certain contrivance in an organ, which causes the notes to sound with rapid pulses or beats, producing a tremulous effect; -- called also {tremolant}, and {tremulant}.