cortex vs exterior

cortex

noun
  • The outer surface of a piece of flint. 

  • The tissue of a stem or root that lies inward from the epidermis, but exterior to the vascular tissue. 

  • The outer layer of an internal organ or body structure, such as the kidney or the brain. 

exterior

noun
  • The outside part, parts or surface of something. 

  • Foreign lands. 

adj
  • Being from outside a country; foreign. 

  • Outdoor. 

  • Relating to the outside parts or surface of something. 

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