decad vs decuplet

decad

noun
  • A group of ten notes from which the consonant triads may be constructed 

decuplet

noun
  • A group of ten notes played in place of four or eight. 

  • A collection of spin-3/2 baryons described in the eightfold way. 

  • One of a group of ten, particularly one of ten babies born to the same mother at one time. 

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