incidence vs recursion

incidence

noun
  • The act of something happening; occurrence. 

  • The falling of a point on a line, or a line on a plane. 

  • The striking of radiation or a projectile upon a surface. 

  • The manner of falling; bearing or onus, as of a tax that falls unequally. 

  • The extent or the relative frequency of something happening. 

  • A measure of the rate of new occurrence of a given medical condition in a population within a specified period of time. 

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. 

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