Definition of "diamond" []

• 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. (noun)
• A piece of jewelry containing such a gemstone. (noun)
• A figure with four equal sides forming two inner obtuse angles and two inner acute angles; a rhombus or lozenge. (noun)
• Games A red, lozenge-shaped figure on certain playing cards. (noun)
• Games A playing card with this figure. (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.

• "-- The real identity of the two words explains Milton’s use of ‘diamond’ in _Paradise Lost_, b. 7; and also in that sublime passage in his _Apology for Smectymnuus_: “Then zeal, whose substance is ethereal, arming in complete _diamond_”."
• "I didn't know that the word diamond comes from the Greek word "Adamas" which means unconquerable."
• "Dayzatari say that diamonds are the thoughts of stars, fallen to earth, and the Pelorian name for diamond translates as "starthought.""