recursion vs relapse

recursion

noun
  • The act of recurring. 

  • The act of defining an object (usually a function) in terms of that object itself. 

  • The invocation of a procedure from within itself. 

relapse

noun
  • The act or situation of relapsing. 

  • An occasion when a person becomes ill again after a period of improvement 

verb
  • To slip or slide back physically; to turn back. 

  • To fall back again; to slide or turn back into a former state or practice. 

  • To return to a vice, especially self-harm or alcoholism, failing to maintain abstinence. 

  • To recur; to worsen, be aggravated (after a period of improvement). 

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