blowhole vs effusion

blowhole

noun
  • A vent for the escape of steam or other gas. 

  • A top-facing opening to a cavity in the ground very near an ocean's shore, leading to a marine cave from which wave water or bursts of air are expelled. 

  • The spiracle, on the top of the head, through which cetaceans breathe. 

  • A vertical opening in the top of a computer case that lets hot air (primarily from the CPU heat sink) escape quickly. 

  • An unintended cavity filled with air in a casting product. 

verb
  • To fill or be filled with air in an unintended cavity. 

effusion

noun
  • A liquid outpouring. 

  • Process of gases passing through a hole or holes considerably smaller than the mean free path of the gas molecules. 

  • An outpouring of speech or emotion. 

  • The seeping of fluid into a body cavity; the fluid itself. 

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