illumination vs rays

illumination

noun
  • Adornment of books and manuscripts with colored illustrations. See illuminate (transitive verb). 

  • Festive decoration of houses or buildings with lights. 

  • Enlightening influence; inspiration. 

  • The act of illuminating, or supplying with light; the state of being illuminated. 

  • Splendour; brightness. 

rays

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