birr vs drone

birr

noun
  • A whirring noise 

  • The currency of Ethiopia, divided into 100 santims. 

  • A strong trilling. 

  • The force of movement; rush, impetus, momentum, driving force 

  • strength, vigor, energy 

verb
  • To make a whirring noise; make a noise like that of revolving wheels, or of millstones at work. 

  • To lurch or set to spinning. 

drone

noun
  • A humming or deep murmuring sound. 

  • One of the fixed-pitch pipes on a bagpipe. 

  • One who performs menial or tedious work. 

  • A person without the ability to think critically and independently, especially one who follows a group blindly; a non-player character. 

  • A remotely controlled aircraft, an unmanned aerial vehicle (UAV). 

  • A Toyota HiAce or a similar van, especially one used by Ugandan state agents to kidnap opposition members. 

  • A male ant, bee or wasp, which does not work but can fertilize the queen. 

  • A genre of music that uses repeated lengthy droning sounds. 

  • A low-pitched hum or buzz. 

verb
  • To speak in a monotone way. 

  • To produce a low-pitched hum or buzz. 

  • To kill with a missile fired by unmanned aircraft. 

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