analogy vs illustration

analogy

noun
  • A relationship of resemblance or equivalence between two situations, people, or objects, especially when used as a basis for explanation or extrapolation. 

  • The proportion or the equality of ratios. 

  • The correspondence of a word or phrase with the genius of a language, as learned from the manner in which its words and phrases are ordinarily formed; similarity of derivative or inflectional processes. 

illustration

noun
  • Something which illustrates; a comparison or example intended to make clear or apprehensible, or to remove obscurity. 

  • A calculated prevision of insurance premiums and returns (life insurance) 

  • The state of being illustrated, or of being made clear and distinct. 

  • A picture designed to decorate a publication, or elucidate a literary work. 

  • The act of illustrating; the act of making clear and distinct; 

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