predecessor vs source

predecessor

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 Usually used to describe an earlier, outdated model. 

  • A vertex having a directed path to another vertex 

source

noun
  • The person, place, or thing from which something (information, goods, etc.) comes or is acquired. 

  • A reporter's informant. 

  • Source code. 

  • The name of one terminal of a field effect transistor (FET). 

  • Spring; fountainhead; wellhead; any collection of water on or under the surface of the ground in which a stream originates. 

verb
  • To obtain or procure: used especially of a business resource. 

  • To find information about (a quotation)'s source (from which it comes): to find a citation for. 

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