letterhead vs vellum

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. 

vellum

noun
  • A writing paper of very high quality. 

  • A type of parchment paper made from the skin of a lamb, baby goat, or calf. 

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