Saturation: The degree of chroma or purity of a color; the degree of freedom from admixture with white.

Definition used with Permission, from
The New Clay : Techniques and Approaches to Jewelry Making
by Nan Roche, Chris Roche (Photographer), Sue Roche (Illustrator), Seymour Bress (Editor)
Paperback - 144 pages Reprint edition (March 1992)
Flower Valley Press, Inc.; ISBN: 0962054348