carol vs level set

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). 

level set

noun
  • An event consisting of level setting 

  • The set of values x for which a real-valued function f(x) is equal to a given constant. 

  • A state of mutual understanding among parties 

verb
  • To establish a baseline of mutual understanding 

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