1. [noun] (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.
2. [noun] A gemstone made from this mineral.
3. [noun] A ring containing a diamond.
4. [noun] A very pale blue color/colour.
5. [noun] Something that resembles a diamond.
6. [noun] (geometry) A rhombus, especially when oriented so that its longer axis is vertical.
7. [noun] (geometry) The polyiamond made up of two triangles.
8. [noun] (baseball) The entire field of play used in the game.
9. [noun] (baseball) The infield of a baseball field.
10. [noun] (card games) A card of the diamonds suit.
11. [adjective] Made of, or containing diamond, a diamond or diamonds.
12. [adjective] Of, relating to, or being a sixtieth anniversary.
13. [adjective] Of, relating to, or being a seventy-fifth anniversary.
14. [verb] To adorn with or as if with diamonds
15. [noun] (printing) (dated) The size of type between brilliant and pearl, standardized as 4½-point.
16. [noun] A transparent piece of diamond that has been cut and polished and is valued as a precious gem.
17. [noun] Very hard native crystalline carbon valued as a gem.
18. [noun] A parallelogram with four equal sides; an oblique-angled equilateral parallelogram.
19. [noun] A playing card in the minor suit that has one or more red rhombuses on it; 'he led a small diamond'; 'diamonds were trumps'.
20. [noun] The area of a baseball field that is enclosed by 3 bases and home plate.
21. [noun] The baseball playing field.
