Source : Webster's Revised Unabridged Dictionary (1913)

Iridescence \Ir`i*des"cence\, n. [See {Iridescent}.]
   Exhibition of colors like those of the rainbow; the quality
   or state of being iridescent; a prismatic play of color; as,
   the iridescence of mother-of-pearl.

Source : WordNet®

iridescence
     n : the visual property of something having a milky brightness
         [syn: {opalescence}]