ballad vs chant

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. 

chant

verb
  • To sing or intone sacred text. 

  • To utter or repeat in a strongly rhythmical manner, especially as a group. 

  • To sing, especially without instruments, and as applied to monophonic and pre-modern music. 

noun
  • Twang; manner of speaking; a canting tone. 

  • Type of singing done generally without instruments and harmony. 

  • A short and simple melody, divided into two parts by double bars, to which unmetrical psalms, etc., are sung or recited. It is the most ancient form of choral music. 

  • A repetitive song, typically an incantation or part of a ritual. 

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