/ ˈdaɪəmənd; NAmE / noun
[ U , C ] a clear precious stone of pure carbon , the hardest substance known. Diamonds are used in jewellery and also in industry, especially for cutting glass :
a ring with a diamond in it
a diamond ring / necklace
She was wearing her diamonds (= jewellery with diamonds in it) .
The lights shone like diamonds.
—see also rough diamond
[ C ] a shape with four straight sides of equal length and with angles that are not right angles
diamonds [ pl. , U ] one of the four suits (= sets) in a pack / deck of cards. The cards are marked with red diamond shapes :
the ten of diamonds
[ C ] a card of this suit :
You must play a diamond if you have one.
[ C ] ( in baseball ) the space inside the lines that connect the four bases ; also used to mean the whole baseball field
Middle English : from Old French diamant , from medieval Latin diamas , diamant- , variant of Latin adamans from Greek adamas , adamant- , untameable, invincible (later used to denote the hardest metal or stone, hence diamond), from a- not + daman to tame.