percolate vs sludge

percolate

noun
  • A liquid that has been percolated. 

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. 

sludge

noun
  • Solids separated from suspension in a liquid. 

  • A residual semi-solid material left from industrial, water treatment, or wastewater treatment processes. 

  • A mass of small pieces of ice on the surface of a body of water. 

  • sludge metal 

  • A sediment of accumulated minerals in a steam boiler. 

verb
  • To slop or drip slowly. 

  • To slump or slouch. 

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