invocation vs recursion

invocation

noun
  • The act of invoking, such as a function call. 

  • The act or form of calling for the assistance or presence of some superior being, especially prayer offered to a divine being. 

  • A call or summons, especially a judicial call, demand, or order. 

  • An act of invoking or claiming a legal right. 

recursion

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

  • The act of recurring. 

  • The invocation of a procedure from within itself. 

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