1) Pipe organ component 
A tremulant (from Latin: tremulus, `trembling`; tremblant) is a device on a pipe organ which varies the wind supply to the pipes of one or more divisions (or, in some cases, the whole organ). This causes their amplitude and pitch to fluctuate, producing a tremolo and vibrato effect. A large organ may have several tremulants, affecting different .....
• (a.) Alt. of Tremulent
A tremulant is a mechanical device for simulating in an organ the effect of the tremolo. It consists of a small box, having a weighted valve upon a spring. This is attached in such a way as to interfere with the pressure of the wind supply when the requisite stop handle is drawn, thus producing a pulsating effect, the frequency of which can be regu...
tremulant That which is characterized by nervousness or shakiness.