nodule vs polyp

nodule

noun
  • A rounded mass or irregular shape; a little knot or lump. 

polyp

noun
  • A cylindrical coelenterate, such as the hydra, having a mouth surrounded with tentacles. 

  • An abnormal growth protruding from a mucous membrane. 

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