knop vs swelling

knop

noun
  • A knob, usually ornamental 

swelling

noun
  • The state of being swollen. 

  • Anything swollen, especially any abnormally swollen part of the body. 

  • A rising, as of passion or anger. 

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