Definition of "domino" []

• A small rectangular wood or plastic block, the face of which is divided into halves, each half being blank or marked by dots resembling those on dice. (noun)
• A game played with a set of these small blocks, generally 28 in number. (noun)
• A country expected to react politically to events as predicted by the domino theory: "The dominos did indeed fall in Indochina” ( Arthur M. Schlesinger, Jr.) (noun)
• A costume consisting of a hooded robe worn with an eye mask at a masquerade. (noun)
• The mask so worn. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Cummings took advantage of what she called a domino effect."
• "George Foster was monkshood, a cambric robe -- a "domino" -- serving to give the blue color note, and a very correct imitation of the flower's helmet answering the purpose of a head-dress."
• "One of those errors involved recreating the so-called domino theory -- the idea that the U.S. had to make a stand in Vietnam, or else Indonesia, Thailand, Burma and the rest of Asia, if not the world, would fall to communism."