from
The Collaborative International Dictionary of English v.0.48
Iridescence \Ir`i*des"cence\, n. [See {Iridescent}.]
Exhibition of colors like those of the rainbow, especially a
surface reflection which changes color with the angle at
which the object is viewed; the quality or state of being
iridescent; a prismatic play of color; as, the iridescence of
mother-of-pearl. It is due to interference of light waves
reflected from the front and back surfaces of a thin layer
transpatrent or semitransparent film.
[1913 Webster]