derm vs exocarp

derm

noun
  • The integument of animal; the skin. 

  • Synonym of dermis. 

  • Guts, entrails. 

exocarp

noun
  • The outermost layer of the pericarp of fruits; the skin or epicarp 

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