chromatic aberration

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Deficiency in clarity of an image produced by a lens, caused by the inability of the lens to bring all colors of light to a focus at the same point.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun optics An optical aberration, in which an image has coloured fringes, caused by differential refraction of light of different wavelengths.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an optical aberration in which the image has colored fringes