hum vs trill

hum

noun
  • An often indistinct sound resembling human humming. 

  • Unpleasant odour. 

  • A phenomenon, or collection of phenomena, involving widespread reports of a persistent and invasive low-frequency humming, rumbling, or droning noise not audible to all people. 

  • Busy activity, like the buzz of a beehive. 

  • A hummed tune, i.e. created orally with lips closed. 

verb
  • To produce low sounds which blend continuously 

  • To express by humming. 

  • To reek, smell bad. 

  • To make a sound from the vocal chords without pronouncing any real words, with one's lips closed. 

  • To drone like certain insects naturally do in motion, or sounding similarly 

  • To buzz, be busily active like a beehive 

intj
  • Synonym of um: a noise indicating doubt, uncertainty, &c. 

  • Synonym of hmm: a noise indicating thought, consideration, &c. 

trill

noun
  • A type of consonantal sound that is produced by vibrations of the tongue against the place of articulation: for example, Spanish ⟨rr⟩, /r/. 

  • A rapid alternation between an indicated note and the one above it, in musical notation usually indicated with the letters tr written above the staff. 

  • A tremulous high-pitched vocal sound produced by cats. 

adj
  • true, respected 

verb
  • To impart the quality of a trill to; to utter as, or with, a trill. 

  • To create a trill sound; to utter trills or a trill; to play or sing in tremulous vibrations of sound; to have a trembling sound; to quaver. 

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