sheet music vs signifier

sheet music

noun
  • Handwritten or printed form of musical notation. 

signifier

noun
  • The sound of a spoken word or string of letters on a page that a person recognizes as a sign. 

  • Something or someone that signifies, makes something more significant or important. 

  • A card representing a querent, question, or situation. 

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