carol vs sing-song

carol

noun
  • A round dance accompanied by singing. 

  • A (usually traditional) religious or secular song sung at Christmastime. 

  • A ballad or song of joy. 

verb
  • To sing carols; especially to sing Christmas carols in a group. 

  • To praise or celebrate in song. 

  • To sing in a joyful manner. 

  • To sing (a song) cheerfully. 

  • To participate in a carol (a round dance accompanied by singing). 

sing-song

noun
  • An informal gathering involving group singing. 

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

adj
  • Like a piece of sing-song; simple and melodic, song-like. 

How often have the words carol and sing-song occurred in a corpus of books? (source: Google Ngram Viewer )