bulla vs vesicle

bulla

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

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

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

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

  • 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) 

vesicle

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

  • A small sac or cyst or vacuole, especially one containing fluid. A blister formed in or beneath the skin, containing serum. A bleb. 

  • A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification. 

  • A membrane-bound compartment found in a cell. 

  • A small sac filled with juice, one of many constituting the pulp of a fruit such as an orange, lemon, or grapefruit. 

  • A pocket of embryonic tissue that is the beginning of an organ. 

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