tremolo vs warble

tremolo

noun
  • A variation in the volume of a note or a chord, evoking a tremor or quiver. 

  • The device in an organ that produces a tremolo effect. 

  • A rapid repetition of the same note, or an alternation between two or more notes. It can also be intended to mean a rapid and repetitive variation in pitch for the duration of a note. It is notated by a strong diagonal bar across the note stem, or a detached bar for a set of notes (or stemless notes). 

warble

noun
  • The sound of one who warbles; singing with trills or modulations. 

  • In naval mine warfare, the process of varying the frequency of sound produced by a narrowband noisemaker to ensure that the frequency to which the mine will respond is covered. 

  • A small hard swelling on a horse's back, caused by the galling of the saddle. 

  • A lesion under the skin of cattle, caused by the larva of a bot fly of genus Hypoderma. 

verb
  • To cause to quaver or vibrate. 

  • To modulate a tone's frequency. 

  • To be quavered or modulated; to be uttered melodiously. 

  • To sing like a bird, especially with trills. 

How often have the words tremolo and warble occurred in a corpus of books? (source: Google Ngram Viewer )