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Coloration of an animal in which the upper side is darker in color than the underside, thought to be a form of camouflage.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
(Zoology) (in the coloration of certain animals) a pattern, serving as camouflage, in which dark colours occur on parts of the body exposed to the light and pale colours on parts in the shade
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
coun•ter•shad•ing(ˈkaʊn tərˌʃeɪ dɪŋ)
(of an animal) coloration that is dark on parts of the body surface that are usu. exposed to the sun and light on parts usu. in shade.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.