diapason vs sinfonietta

diapason

noun
  • The musical octave. 

  • The range or scope of something, especially of notes in a scale, or of a particular musical instrument. 

  • A harmonious outpouring of sound. 

  • A tonal grouping of the flue pipes of a pipe organ. 

sinfonietta

noun
  • A small orchestra. 

  • A small-scale symphony (either in length or size of orchestra needed). 

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