Other forms: diamonds
A diamond is the hardest natural substance and the most valued of the clear gemstones — a diamond ring, a diamond the size of a pea. It is pure carbon under enormous pressure, which is the same element as pencil lead and coal.
The word also names a shape: a square standing on one corner, which is what a playing card diamond is and what road signs use. Diamonds is one of the four suits in a pack of cards. And a rough diamond is a person of real worth and no polish, which is a compliment in Britain and needs explaining almost anywhere else. Note the pronunciation: two syllables in careful speech, DY-mund, though three is heard.
1nounhardA very hard, clear precious stone.
“The ring has a single diamond in it.”
2noundiamondA shape with four equal sides standing on one corner.
“The sign is a yellow diamond.”
3nounsuitsOne of the four suits in a pack of playing cards.
“He led with the ace of diamonds.”
Too few real examples of this word to estimate which sense is commonest.
diamond is a precious stone, or a shape.
Latin adamas meant the hardest metal or stone, from Greek adamas — a-, not, plus daman, to tame. A diamond is literally the untameable thing, and the same Greek word gives English adamant, meaning immovable.
Middle English
dyamaunt
English, today
diamond
From Middle English dyamaunt. From Middle English dyamaunt, from Old French diamant, from Latin diamās, from Latin adamās, from Ancient Greek ἀδάμᾱς (“diamond”). a doublet of adamant. The printing sense is a Dutch diamant, used by Dirck Voskens who first cut it around 1700; compare pearl, ruby (“size of type between pearl and nonpareil”).
Etymology from Wiktionary, CC BY-SA