black and tan

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

• noun An alcoholic beverage made from a dark and a light malt, typically Guinness or Beamish stout (black) and Bass or Harp ale (tan). In the United Kingdom, the liquids are mixed together. In the U.S., the heavier liquid fills the bottom of the glass, and the other is poured over a spoon to avoid mixing.

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

• noun an English recruit (who wore a uniform that was black and tan) serving in the Irish constabulary to suppress the Sinn Fein rebellion of 1919 to 1921