cortex vs peeling

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. 

peeling

noun
  • Strips of an outer rind or surface that has been removed. 

  • The act of removing the outer surface in strips. 

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