Black? and Tan? n., pl. Black and Tans. a member of an armed force sent by the British government to Ireland in 1920 to suppress revolutionary activity: so called from the color of their uniforms. black?-and-tan? adj. (of a dog) being of a black color with tan markings above the eyes and on the muzzle, chest, legs, feet, and breech. [1855?60] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.