cortex vs derma

cortex

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

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

  • The outer surface of a piece of flint. 

derma

noun
  • The inner layer of the skin. 

  • A Jewish dish of roast or boiled seasoned meat and flour etc. in a casing, especially kishke. 

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