nodus vs sitch

nodus

noun
  • A difficulty. 

  • In the Odonata, a prominent crossvein near the centre of the leading edge of a wing. 

sitch

noun
  • Situation. 

  • A brook; ditch; gutter; drain; ravine. 

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