diamond /ˈdaɪ.ə.mənd/noun 13adjective 4verb 1forms 3 noun13 •a costly stone with no color that shines brightly when cut and is harder than anything in natureThe dozen loose diamonds sparkled in the light. •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. •A card of the diamonds suit.I have only one diamond in my hand. •A rhombus, especially when oriented so that its longer axis is vertical.An adder writhes out of the bush, I can see the diamonds on its back; it shrithes across the sandy soil, and bites the right foot of one of the knights. — 2003 •A polyiamond consisting of two triangles. •The entire field of play used in the game. •The infield of a baseball field.The teams met on the diamond. •A diamond ring.What a beautiful engagement diamond. •Something that resembles a diamond. •A very pale blue color. •A town square. •(old-fashioned) The size of type between brilliant and pearl, standardized as 4+¹⁄₂-point. •Sable, when blazoning by precious stones.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. — 1720 adjective4 •Made of, or containing diamond, a diamond or diamonds.He gave her diamond earrings. •Of, relating to, or being a sixtieth anniversary.Today is their diamond wedding anniversary. •Of, relating to, or being a seventy-fifth anniversary.Today is their diamond wedding anniversary. •(slang) First-rate; excellent.He's a diamond geezer. verb1 •To adorn with or as if with diamonds. formsdiamonded · diamonding · diamonds