causation vs source

causation

noun
  • The act of causing. 

  • The act or agency by which an effect is produced. 

  • Cause and effect, considered as a system. 

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 causation and source occurred in a corpus of books? (source: Google Ngram Viewer )