Source : Webster's Revised Unabridged Dictionary (1913)

Percolation \Per`co*la"tion\, n. [L. percolatio.]
   The act or process of percolating, or filtering; filtration;
   straining. Specifically (Pharm.), the process of exhausting
   the virtues of a powdered drug by letting a liquid filter
   slowly through it.

Source : WordNet®

percolation
     n 1: the slow passage of a liquid through a filtering medium;
          "the percolation of rainwater through the soil"; "the
          infiltration of seawater through the lava" [syn: {infiltration}]
     2: the act of making coffee in a percolator
     3: the filtration of a liquid for extraction or purification