vibrato vs. tremolo

noun

Music.

plural

vibratos 
  1. a pulsating effect, produced in singing by the rapid reiteration of emphasis on a tone, and on bowed instruments by a rapid change of pitch corresponding to the vocal tremolo.

noun

Music.

plural

tremolos 
  1. a tremulous or vibrating effect produced on certain instruments and in the human voice, as to express emotion.

  2. a mechanical device in an organ by which such an effect is produced.