ballad vs glee

ballad

verb
  • To compose or sing ballads. 

noun
  • A slow romantic song. 

  • A kind of narrative poem, adapted for recitation or singing; especially, a sentimental or romantic poem in short stanzas. 

glee

verb
  • To sing a glee (unaccompanied part song). 

noun
  • Music; minstrelsy; entertainment. 

  • Joy; happiness; great delight, especially from one's own good fortune or from another's misfortune. 

  • An unaccompanied part song for three or more solo voices, not necessarily merry. 

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