The Collaborative International Dictionary
Decantation \De`can*ta"tion\ (?; 277), n. [Cf. F. d['e]cantation.] The act of pouring off a clear liquor gently from its lees or sediment, or from one vessel into another.
Wiktionary
n. the act of decanting the supernatant liquid from a solid sediment
Wikipedia
Decantation is a process for the separation of mixtures, by removing a layer of liquid, generally one from which a precipitate has settled. The purpose may be either to produce a clean decant, or to remove undesired liquid from the precipitate (or other layers). If the aim is to produce a clean solution, a small amount of solution must generally be left in the container, and care must be taken to prevent any precipitate from flowing with the solution out of the container.
Usage examples of "decantation".
The silica is washed by decantation two or three times with hydrochloric acid and hot water, before being thrown on to the filter.