inscription vs memorandum

inscription

noun
  • Words written in the front of a book as a dedication. 

  • Text carved on a wall or plaque, such as a memorial or gravestone. 

  • The text on a coin. 

  • The act of inscribing. 

memorandum

noun
  • A short note serving as a reminder. 

  • A brief diplomatic communication. 

  • A written business communication. 

  • A page in an annual publication honoring the memory of a person who died during the past year. 

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