1. In orchestral music, the rapid reiteration of the same note played by quickly reversing the bow on violins and other stringed instruments. 2. In pipe organs, mainly theatre organs, repeatedly varying the pitch and loudness of the pipes by shaking the wind supply in imitation of vibrato. 3. In dance organs, General Tremolo rapidly interrupts the wind supply to provide rapidly-repeated notes, and Jazz Tremolo rapidly shakes the wind supply to imitate the vibrato of clarinets and saxophones in 1940s dance bands. In orchestrions, tremolo is used synonymously with vibrato. 4. The mechanism used for producing vibrato or tremolo in an organ or orchestrion.