centenarian vs grandfather

centenarian

noun
  • One who or that which is at least 100 years old. 

adj
  • Aged 100 years or more; extremely old. 

  • Of or relating to centenarians or a centenary celebration. 

grandfather

noun
  • A male forefather. 

  • A father of someone's parent. 

  • 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. 

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