canteen vs gravity bong

canteen

noun
  • A water bottle, flask, or other vessel, typically used by a soldier or camper as a bottle for carrying water or liquor for drink 

  • A small cafeteria or snack bar, especially one in a military establishment, school, or place of work. 

  • A temporary or mobile café used in an emergency or on a film location etc. 

  • A military mess kit. 

  • A box with compartments for storing eating utensils, silverware etc. 

gravity bong

noun
  • A homemade device used to smoke marijuana, consisting of a plastic jug with the bottom cut out and immersed in a vat of water, which is then raised to create a vacuum beneath its bowl of lit marijuana. 

  • Synonym of waterfall bong 

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