pentet vs quintuplet

pentet

noun
  • Synonym of quintet 

  • In NMR spectroscopy, a group of five peaks whose intensity is in the ratio 1:4:6:4:1. Note, that "pentet" is a non-standard notation; it should be replaced by "quintet" (compare "quartet" and "triplet" are also based on Latin numbering). 

quintuplet

noun
  • A group of five, particularly (music) a tuplet of five notes to be played in the time for four. 

  • A cycle adapted for five riders, all of whom can assist in the propulsion. 

  • One of a group of five, particularly babies born from the same mother during the same birth. 

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