motet vs singsong

motet

noun
  • A composition adapted to sacred words in the elaborate polyphonic church style; an anthem. 

singsong

noun
  • A piece of verse with a simple, song-like rhythm. 

  • A drawling or monotonous tone, as of a badly executed song. 

  • Bad singing or poetry. 

  • An informal gathering at which songs are sung; a singing session. 

verb
  • To utter in a singsong voice. 

adj
  • Like a piece of singsong; simple and melodic, varying in pitch (of tone of voice etc.) 

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