grandfather vs predecessor

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. 

predecessor

noun
  • A model or type of machinery or device which precedes the current (or later) one. Usually used to describe an earlier, outdated model. 

  • One who precedes; one who has preceded another in any state, position, office, etc.; one whom another follows or comes after, in any office or position. 

  • A vertex having a directed path to another vertex 

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