Source : Webster's Revised Unabridged Dictionary (1913)

Saturation \Sat`u*ra"tion\, n. [L. saturatio: cf. F.
   saturation.]
   1. The act of saturating, or the state of being saturating;
      complete penetration or impregnation.

   2. (Chem.) The act, process, or result of saturating a
      substance, or of combining it to its fullest extent.

   3. (Optics) Freedom from mixture or dilution with white;
      purity; -- said of colors.

   Note: The degree of saturation of a color is its relative
         purity, or freedom from admixture with white.

Source : WordNet®

saturation
     n 1: the process of totally saturating something with a
          substance; "the impregnation of wood with preservative";
          "the saturation of cotton with ether" [syn: {impregnation}]
     2: the act of soaking thoroughly with a liquid
     3: a condition in which a quantity no longer responds to some
        external influence
     4: chromatic purity: freedom from dilution with white and hence
        vividness of hue [syn: {chroma}, {intensity}, {vividness}]