percolation

from The Century Dictionary.

• noun The act of percolating; the act of straining or filtering; filtration; the act of passing through small interstices, as liquor through felt or a porous stone.
• noun In pharmacy, the process of extracting the soluble parts of powdered substances by passing through them successive quantities of a solvent which yields a clear extract free from insoluble matters: used in the sense of displacement.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun the seepage or filtration of a liquid through a porous substance

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the act of making coffee in a percolator
• noun the filtration of a liquid for extraction or purification
• noun the slow passage of a liquid through a filtering medium