Definition of "diamond" in English

noun

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.

   • The dozen loose diamonds sparkled in the light.

3. A diamond ring.

   • What a beautiful engagement diamond.

4. A very pale blue color.

5. (heraldry) Sable, when blazoning by precious stones.

6. Something that resembles a diamond.

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

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

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

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

    • 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.

adjective

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

   • 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.

verb

1. To adorn with or as if with diamonds.