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dom·i·no 1 (dŏmə-nō)
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n. pl. dom·i·noes or dom·i·nos
1.
a. 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.
b. dominoes or dominos (used with a sing. or pl. verb) A game played with a set of these small blocks, generally 28 in number.
2. 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.)

[French, probably from domino, mask, perhaps because of the resemblance between the eyeholes and the spots on some of the tiles; see DOMINO2.]
(click for a larger image)
domino1

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
dom·i·no 2 (dŏmə-nō)
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n. pl. dom·i·noes or dom·i·nos
1.
a. A costume consisting of a hooded robe worn with an eye mask at a masquerade.
b. The mask so worn.
2. One wearing this costume.

[French, probably from Latin (benedīcāmus) dominō, (let us praise) the Lord, dative of dominus, lord; see dem- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
Dom·i·no (dŏmə-nō), Fats Originally Antoine Domino. Born 1928.
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American singer, pianist, and songwriter whose popular rhythm and blues songs include "Ain't It a Shame" (1955).
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Fats Domino
photographed in 2006

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

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