epigraph vs lettering

epigraph

noun
  • A literary quotation placed at the beginning of a book or other text. 

  • An inscription, especially on a building. 

  • The set of all points lying on or above the function's graph. 

verb
  • To provide (a literary work) with an epigraph. 

lettering

noun
  • Written text, especially when printed. 

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