melody vs tenson

melody

noun
  • A sequence of notes that makes up a musical phrase 

tenson

noun
  • A form of lyric poem used by troubadours in Provençal in which two voices present different sides of an argument, in alternate stanzas, lines, or groups of lines with identical structure. 

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