headword vs signification

headword

noun
  • Any word which may be modified by an adjunct. 

  • A word used as the title of a section, particularly in a dictionary, encyclopedia, or thesaurus. 

signification

noun
  • A meaning of a word. 

  • Evidence for the existence of something. 

  • The act of signifying, or something that is signified; significance. 

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