bookfell vs letterhead

bookfell

noun
  • A skin prepared for writing upon; a sheet of vellum or parchment; paper. 

  • A vellum or parchment manuscript. 

letterhead

noun
  • Paper marked with a letterhead. 

  • A portion of text at the top of a letter, identifying the sender and often giving their address etc., used for formal correspondence. 

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