blowhole vs slit

blowhole

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

noun
  • 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. 

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

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

slit

verb
  • To cut a narrow opening. 

  • To split into strips by lengthwise cuts. 

  • To cut; to sever; to divide. 

adj
  • Having a cut narrow opening 

noun
  • A narrow cut or opening; a slot. 

  • The opening of the vagina. 

  • A woman, usually a sexually loose woman; a prostitute. 

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