DIAMOND

—noun 

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1. a pure or nearly pure, extremely hard form of carbon, naturally crystallized in the isometric system.

2. a piece of this stone.

3. a transparent, flawless or almost flawless piece of this stone, especially when cut and polished, valued as a precious gem.

4. a ring or other piece of jewelry containing such a precious stone, especially an engagement ring.

5. a piece of this stone used in a drill or cutting tool.

6. a tool provided with such an uncut stone, used for cutting glass.

7. crystallized carbon, or a piece of it, artificially produced.

8. an equilateral quadrilateral, especially as placed with its diagonals vertical and horizontal; a lozenge or rhombus.

9. any rhombus-shaped figure or object oriented with its diagonals vertical and horizontal.

10. a red rhombus-shaped figure on a playing card.

11. a card of the suit bearing such figures.

12. diamonds, (used with a singular or plural verb) the suit so marked: Diamonds is trump. Diamonds are trump.

13. Baseball.

    1. the space enclosed by home plate and the three bases; infield.

    2. the entire playing field.

14. Printing. a 4½-point type of a size between brilliant and pearl.

 

—adjective 

1. made of or set with a diamond or diamonds.

2. having the shape of a diamond: a dress with a diamond print.

3. indicating the 75th, or sometimes the 60th, event of a series, as a wedding anniversary. See table under wedding anniversary.

 

—verb (used with object) 

1. to adorn with or as if with diamonds.

 

—Idioms 

1. diamond in the rough, a person of fine character but lacking refined manners or graces.