ballad vs psalmody

ballad

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

  • A slow romantic song. 

verb
  • To compose or sing ballads. 

psalmody

noun
  • The singing or the writing of psalms. 

  • A collection of psalms. 

verb
  • To celebrate in psalms. 

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