- 1[uncountable, countable] a clear precious stone of pure carbon, the hardest substance known. Diamonds are used in jewelry and also in industry, especially for cutting glass. a ring with a diamond in it a diamond ring/necklace She was wearing her diamonds (= jewelry with diamonds in it). The lights shone like diamonds.
- 2[countable] a shape with four straight sides of equal length and with angles that are not right angles
- 3diamonds [plural] one of the four suits (= sets) in a deck of cards. The cards are marked with red diamond shapes the ten of diamonds Diamonds are trump cards in this game.
- 4[countable] a card of this suit You must play a diamond if you have one.
- 5[countable] (in baseball) the space inside the lines that connect the four bases; also used to mean the whole baseball field Idioms
a person who has many good qualities even though they do not seem to be very polite, educated, etc.
Check pronunciation: diamond