duo vs nonet

duo

noun
  • Two people who work or collaborate together as partners; especially, those who perform music together. 

  • Any cocktail consisting of a spirit and a liqueur. 

  • Any pair of two people. 

  • A song in two parts; a duet. 

nonet

noun
  • A composition for nine instruments or nine voices. 

  • A byte of nine bits. 

  • A group of nine nuclear or subatomic particles. 

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