The Collaborative International Dictionary of English v.0.48:
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.
[1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Tremulant \Trem"u*lant\, Tremulent \Trem"u*lent\, a.
Tremulous; trembling; shaking. [R.] " With tremulent white
rod." --Carlyle.
[1913 Webster]