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 (dī′ə-mənd, dī′mənd)
1. An extremely hard, highly refractive crystalline form of carbon that is usually colorless and is used as a gemstone and in abrasives, cutting tools, and other applications.
2. A piece of jewelry containing such a gemstone.
3. A rhombus, particularly when oriented so that one diagonal extends from left to right and the other diagonal extends from top to bottom.
4. Games
a. A red, lozenge-shaped figure on certain playing cards.
b. A playing card with this figure.
c. diamonds(used with a sing. or pl. verb) The suit of cards represented by this figure.
5. Baseball
a. The infield.
b. The whole playing field.
Of or relating to a 60th or 75th anniversary.
tr.v. di·a·mond·ed, di·a·mond·ing, di·a·monds
To adorn with diamonds.
diamond in the rough
One having exceptionally good qualities or the potential for greatness but lacking polish and refinement.

[Middle English diamaunt, from Old French diamant, from Medieval Latin diamās, diamant-, alteration of Latin adamās; see adamant.]
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.