Saturation

In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a precipitate. This point of maximum concentration, the saturation point, depends on the temperature of the liquid as well as the chemical nature of the substances involved. If a change in conditions (e.g. cooling) means that the concentration is actually higher than the saturation point, the solution has become supersaturated.

For more, visit the Wikipedia entry for saturation, URL: http://en.wikipedia.org/wiki/Saturation_(chemistry)