monody vs threnode

monody

noun
  • An ode, as in Greek drama, for a single voice, often specifically a mournful song or dirge. 

  • Any poem mourning the death of someone; an elegy. 

  • A composition having a single melodic line. 

  • A monotonous or mournful noise. 

threnode

noun
  • A threne, or threnody; a dirge; a funeral song. 

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