nervure vs vas

nervure

noun
  • A vein in the wing of an insect. 

  • One of the ribs in a groined vault; a projecting moulding. 

vas

noun
  • A vessel or duct transporting any bodily fluid, such as blood, lymph, chyle, or semen. 

  • The vas deferens. 

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