diamond

DY-uh-muhnd/ˈdaɪ.ə.mənd/

15 meanings of diamond

1
gemstonenouncountable or uncountable
A very hard, clear crystalline form of pure carbon, valued as a precious gemstone and used in cutting tools.
The appraiser examined the diamond under a bright lamp.
Diamonds sold by reputable jewelers are typically graded for color and clarity.
UsageSay diamonds for stones you could hold, and bare diamond for the kind of stone: harder than diamond.
2
made of gemsadjective
Made of diamond, or set or tipped with one or more diamonds.
Her diamond earrings caught the light every time she turned her head.
Crews used a diamond blade to slice through the concrete slab.
Similardiamantine
3
four-sided shapenouncountable or uncountable
A rhombus, especially one positioned so that its longer axis runs vertically.
The road sign ahead was a yellow diamond with a black arrow pointing left.
Fold the napkin into a diamond and set it point-up on the plate.
UsageOften diamond-shaped; things are cut or folded into a diamond.
Similarlozenge, rhombus
Note
Geometry's everyday name for the rhombus, and orientation decides it. A figure standing on one point reads as a diamond, while rhomb, rhombus and lozenge suit the same shape in other settings. The word does descriptive work far from mathematics: Kevin Crossley-Holland's adder has diamonds on its back. The playing-card suit and the baseball infield both borrow this shape.
Checked 31 Oct 2026 · 3 facts
Kevin Crossley-Holland describes an adder with diamonds on its back. en.wiktionary.org
The playing-card suit takes its name from the diamond shape. en.wikipedia.org
The baseball infield is called a diamond because of its shape. en.wikipedia.org
4
sparkling thingnouncountable or uncountable
Something that resembles a diamond, whether in sparkle or in shape.
The waterfall's spray threw diamonds into the morning sunlight.
Far below, the city was a diamond of light against the dark coast.
Similarjewel, gem
5
baseball fieldnouncountable or uncountable
In baseball, the infield marked out by the four bases, or the whole playing field.
Groundskeepers spent the morning preparing the diamond for the doubleheader.
By the seventh inning, fog covered the diamond from home plate to the outfield wall.
Similarinfield, baseball field
Note
The name properly belongs to the square infield marked out by the bases and has spread to the whole playing area, outfield included. In this wider use it competes with plainer terms such as ball field and baseball field.
Checked 2 Nov 2026 · 1 fact
The bases mark out a square infield. en.wikipedia.org
6
playing cardnouncountable or uncountable
A playing card belonging to the suit whose symbol is a red, diamond-shaped figure.
She led a low diamond, hoping her partner held the ace.
Three diamonds appeared on the flop, and he started betting hard.
UsageOne card is a diamond; the suit is diamonds: the ace of diamonds, lead in diamonds.
7
sixty yearsadjective
Marking a sixtieth anniversary, or sometimes a seventy-fifth.
Queen Elizabeth II's diamond jubilee in 2012 marked sixty years on the throne.
They renewed their vows at their diamond wedding anniversary, sixty years after the original ceremony.
UsageUsually diamond jubilee, diamond wedding or diamond anniversary. Give the number when it matters, since it can mean 60 or 75.
Note
Here the word names two different anniversaries. The sixtieth is one, and the seventy-fifth is the other, and the same phrase, a diamond wedding anniversary, can mean either. Nothing in the phrase decides between them.
Checked 2 Nov 2026 · 1 fact
A diamond wedding anniversary can mark either sixty or seventy-five years; the phrase alone does not specify which. en.wiktionary.org
8
engagement ringnouncountable or uncountable
A ring set with a diamond.
He returned the diamond to the jeweler after the engagement ended.
She twisted the diamond around her finger nervously during the interview.
Similarring
9
excellentadjectiveslangBritish
Of the very best kind; excellent.
My brother-in-law is a diamond bloke who drove three hours at midnight to jump-start my car.
Our new neighbor is a diamond geezer who lends us his tools without being asked.
UsageUse diamond before a noun, especially in a diamond geezer, to praise someone.
Similargreat, excellent, terrific, brilliant
Oppositeterrible, lousy
Note
Slang praise aimed at people more than things, best known in diamond geezer, a warm compliment for a reliable man.

Less common meanings

10
town squarenoundialectalPennsylvaniaWesterncountable or uncountable
An open public square at the center of a town.
A war memorial stands at the center of the diamond, where the town's two main streets cross.
Shops and cafés around the diamond stay busy on market days.
Similarsquare, plaza
Note
A regional word of Pennsylvania, especially Western Pennsylvania, and of Ulster towns such as Donegal and Monaghan, where a town's central square is the diamond, and often the Diamond, used as a proper name. Elsewhere in American English the same place is usually called the square.
11
triangle pairnouncountable or uncountable
The polyiamond made up of two equilateral triangles joined along a shared edge.
Among polyiamonds, the diamond is the only shape made from exactly two triangles.
Each tile in the floor pattern was a diamond built from two equilateral triangles.
Note
Tiling mathematics turns the word back on itself. The family name polyiamond is cut from diamond, and the systematic synonym 2-iamond counts the triangles. Two equilateral triangles sharing an edge make a rhombus with angles of 60 and 120 degrees. So every diamond in this sense is also the everyday geometric diamond, though not every rhombus qualifies.
Checked 31 Oct 2026 · 5 facts
The word polyiamond is formed from diamond. en.wiktionary.org
2-iamond is a synonym of diamond and denotes a polyiamond consisting of two triangles. en.wiktionary.org
Joining two equilateral triangles along an edge produces a rhombus with angles of 60 and 120 degrees. en.wikipedia.org
A diamond polyiamond is also a diamond in the ordinary geometric sense. en.wiktionary.org
Not every rhombus is a diamond polyiamond. tasks.illustrativemathematics.org
12
noundatedcountable or uncountable
A size of type between brilliant and pearl, standardized as four-and-a-half-point.
Note
A printer's word with Dutch roots: it calques Dutch diamant, the name given by Dirck Voskens, who first cut the size around 1700. Its neighbors, brilliant and pearl, are jewel names too, so the tiniest types were named like gems. Named sizes have given way to points, which is why the sense is dated.
Checked 2 Nov 2026 · 5 facts
The printing sense is a calque of Dutch diamant. en.wiktionary.org
Dirck Voskens introduced the name and first cut the type around 1700. en.wiktionary.org
Brilliant is a gemstone name as well as the name of the neighboring smaller type size. en.wiktionary.org
Pearl is a jewelry term as well as the name of the neighboring larger type size. en.wiktionary.org
Diamond corresponds to 4½-point, between brilliant at 4 points and pearl at 5 points. en.wikipedia.org
13
verbrare
To deck something with diamonds, or make it glitter as though diamonds had been scattered over it.
14
nounrare
A very pale blue color.
15
noun
The heraldic color black (sable), in the system of blazoning arms by precious stones.
Pearl, an Eagle, Diamond, between three Crosses Patee, Ruby, for Morrys.
1754, John Lodge, The Peerage of Ireland

Practice

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Origin

Ancient Greek ἀδάμᾱς (adámās, "diamond") passed into Latin as adamās and Late Latin as diamās, then into Old French as diamant and Middle English as dyamaunt. Adamant is a doublet. In printing, the name of the type size is a calque of Dutch diamant, the term used by Dirck Voskens, who first cut that size around 1700.