describe vs illustrate

describe

verb
  • To represent by drawing; to draw a plan of; to delineate; to trace or mark out. 

  • To give rise to a geometrical structure. 

  • To represent in words. 

  • To introduce a new taxon to science by explaining its characteristics and particularly how it differs from other taxa. 

illustrate

verb
  • To provide a book or other publication with pictures, diagrams or other explanatory or decorative features. 

  • To clarify something by giving, or serving as, an example or a comparison. 

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