predecessor vs prior

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 Usually used to describe an earlier, outdated model.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 

prior

noun
  • A belief supported by previous evidence or experience that one can use to make inferences about the future. 

  • A high-ranking member of a monastery, usually lower in rank than an abbot. 

  • A prior probability distribution, one based on information or belief before additional data is collected. 

  • A chief magistrate in Italy. 

  • A previous arrest or criminal conviction on someone's record. 

adv
  • Previously. 

adj
  • Former, previous. 

  • Advance; previous; coming before. 

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