Pa vs Pop

Pa

noun
  • A short form of grandpa; grandfather. 

  • Father, dad, papa. 

Pop

name
  • Traditional nickname for a stage doorman. 

noun
  • The body of college prefects. 

  • A popular classical music concert. 

  • A social club and debating society at Eton College. 

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