epigraph vs epitaph

epigraph

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

epitaph

verb
  • To write or speak after the manner of an epitaph. 

  • To commemorate by an epitaph. 

noun
  • An inscription on a gravestone in memory of the deceased. 

  • A poem or other short text written in memory of a deceased person. 

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