kick-off vs scrimmage

kick-off

noun
  • The opening kick of each half of a game of football. 

  • The opening sequence of any event. 

  • The opening sequence of notes in a song, usually played by the song's main instrument, to indicate the beginning of the song. 

scrimmage

noun
  • In American football or Canadian football, a play that begins with a snap from the center while opposing teams are on either side of a line of scrimmage. 

  • A rough fight. 

  • In some team sports, especially soccer, a practice game which does not count on a team's record. 

verb
  • To have, or be involved in, a scrimmage. 

How often have the words kick-off and scrimmage occurred in a corpus of books? (source: Google Ngram Viewer )