nickname vs proper noun

nickname

noun
  • A familiar, shortened or diminutive name for a person or thing. 

  • A familiar, invented name for a person or thing used instead of the actual name of the person or thing, often based on some noteworthy characteristic. 

verb
  • To give a nickname to (a person or thing). 

proper noun

noun
  • A word or phrase that is a noun denoting a particular person, place, organization, ship, animal, event, or other individual entity. 

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