diamond

From Middle English dyamaunt, from Old French diamant, from Late Latin diamas, from Latin adamas, from Ancient Greek ἀδάμας (adámas, “diamond”). Doublet of adamant. The printing sense is a calque of Dutch diamant, used by Dirck Voskens who first cut it around 1700; compare pearl, ruby (“size of type between pearl and nonpareil”).

• IPA^(key): /ˈdaɪ.(ə.)mənd/

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diamond (countable and uncountable, plural diamonds)

1. (uncountable) A glimmering glass-like mineral that is an allotrope of carbon in which each atom is surrounded by four others in the form of a tetrahedron.

   The saw is coated with diamond.

   synthetic diamond

2. A gemstone made from this mineral.

   Synonym: (informal) sparkler

   The dozen loose diamonds sparkled in the light.

   • 2012 March, Lee A. Groat, “Gemstones”, in American Scientist‎, volume 100, number 2, archived from the original on 14 June 2012, page 128:

     Although there are dozens of different types of gems, among the best known and most important are diamond, ruby and sapphire, emerald and other gem forms of the mineral beryl, chrysoberyl, tanzanite, tsavorite, topaz and jade.

3. A diamond ring.

   What a beautiful engagement diamond.

4. A very pale blue color.

   diamond:  

5. (heraldry) Sable, when blazoning by precious stones.
   • 1720, Francis Nichols, Rudiments of Honour, page 296:

     Elphingston. Pearl a Chevron Diamond between three Boars Heads Eraz'd Ruby, arm'd of the first. / Eymouth. Diamond a Lyon Rampant Pearl, on a Canton of the 2d, a Cross Ruby.

   • 1726, John Guillim, The Banner Display'd; Or, an Abridgment of Guillim, page 504:

     The Field is Ruby, on a Bend Topaz, three Martlets Diamond. The Armes of the most Noble and Puissant Lord, Edward Brabazon, Earl of Meath, and Baron of Atherdee in the Kingdom of Ireland. His Lordship's Atchievements are Quarterly of sixteen Coats. 1. Brabazon, as above. 2. Diamond, on a Chevron between three Pickaxes Pearl, as many Mullets Ruby, by the Name of Mosley. 3. Saphire, ten Bezants, 4, 3, 2, 1, by the Bisset.

   • 1754, John Lodge, The Peerage of Ireland; Or, a Genealogical History of the ..., page 71:

     Pearl, an Eagle, Diamond, between three Crosses Patee, Ruby, for Morrys.

6. Something that resembles a diamond.

   Synonym: adamant

7. (geometry) A rhombus, especially when oriented so that its longer axis is vertical.

   Synonyms: lozenge, rhomb

8. (geometry) The polyiamond made up of two triangles.

   Synonym: 2-iamond

9. (baseball) The entire field of play used in the game.

   Synonyms: ball field, baseball field

10. (baseball) The infield of a baseball field.

    Synonyms: baseball diamond, infield

    Antonym: outfield

    The teams met on the diamond.

11. (card games) A card of the diamonds suit.

    I have only one diamond in my hand.

12. (Western Pennsylvania) A town square.
13. (printing, dated) The size of type between brilliant and pearl, standardized as 4+¹⁄₂-point.

• demantoid
• diamantine

• argyle
• carbonado
• diamante
• paragon
• chlenter
• rhinestone
• brifka

diamond (not comparable)

1. Made of, or containing diamond, a diamond or diamonds.

   Synonym: diamantine

   He gave her diamond earrings.

2. Of, relating to, or being a sixtieth anniversary.

   Today is their diamond wedding anniversary.

3. Of, relating to, or being a seventy-fifth anniversary.

   Today is their diamond wedding anniversary.

4. (slang) First-rate; excellent.

   He's a diamond geezer.

   (The addition of quotations indicative of this usage is being sought:)

diamond (third-person singular simple present diamonds, present participle diamonding, simple past and past participle diamonded)

1. To adorn with or as if with diamonds.

• David Barthelmy (1997–2024) “Diamond”, in Webmineral Mineralogy Database.
• “diamond”, in Mindat.org‎, Hudson Institute of Mineralogy, 2000–2024.
• Jonathon Green (2024) “diamond n.”, in Green’s Dictionary of Slang
• Jonathon Green (2024) “diamond adj.”, in Green’s Dictionary of Slang
• Eric Partridge (2005) “diamond”, in Tom Dalzell and Terry Victor, editors, The New Partridge Dictionary of Slang and Unconventional English, volumes 1 (A–I), London, New York, N.Y.: Routledge, →ISBN, page 580.