bulla vs polyp

bulla

noun
  • A blister, vesicle, or other thin-walled cavity or lesion, as 

  • A rich Jamaican cake made with molasses and spiced with ginger and nutmeg. 

  • In ancient Rome, a kind of amulet or boss. 

  • (usually and especially) Such a blister that is more than 5 mm in diameter. 

  • A clay envelope or hollow ball, typically with seal impressions or writing on its outside indicating its contents. 

  • Later, a handwritten document from the papal chancellery. 

  • The tympanic part of a temporal bone (having a bubble-like appearance) 

polyp

noun
  • An abnormal growth protruding from a mucous membrane. 

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

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