percolate vs waterfall

percolate

verb
  • To pass a liquid through a porous substance; to filter. 

  • To make (coffee) in a percolator. 

  • To drain or seep through a porous substance. 

  • To spread slowly or gradually; to slowly become noticed or realised. 

noun
  • A liquid that has been percolated. 

waterfall

verb
  • To drink (something) from a container by pouring it from a height so as not to touch one's lips to the rim. 

  • To fall like a waterfall. 

  • Synonym of recycle 

noun
  • A waterfall-like outpouring of liquid, smoke, etc. 

  • A flow of water over the edge of a cliff. 

  • Waterfall model 

  • The action of drinking from a vessel without touching it with the lips, considered more sanitary for a shared vessel. 

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