grandfather vs nana

grandfather

noun
  • A father of someone's parent. 

  • A male forefather. 

  • The archived older version of a file that immediately preceded the father file. 

verb
  • To retain discontinued laws or rules for (a thing, person or organization previously affected by them). 

  • To be, or act as, a grandfather to. 

nana

noun
  • One's grandmother. 

  • A nanny. 

  • A banana. 

  • A foolish person. 

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