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• di
  di

  preposition

  from; of: used in Italian personal names, originally to indicate place of origin.
• Di
  Di

  noun

  a female given name, form of Diana.
• DI
  DI

  Department of the Interior.
• di-
  di-

  a prefix occurring in loanwords from Greek, where it meant “two,” “twice,” “double” (diphthong ); on this model, freely used in the formation of compound words (dicotyledon; dipolar ) and in chemical terms (diatomic; disulfide ).
• di.
  di.

  abbreviation

  diameter.
• di–
  di–

  A prefix that means “two,” “twice,” or “double.” It is used commonly in chemistry, as in dioxide, a compound having two oxygen atoms.

di

¹ American  

[dee] / di /

Or Di

preposition

1. from; of: used in Italian personal names, originally to indicate place of origin.

   Conte di Savòia.

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di ² American  

[dee] / di /

noun

Music.

1. a tone in the ascending chromatic scale between do and re.

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Di ³ American  

[dahy] / daɪ /

noun

1. a female given name, form of Diana.

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Di ⁴ American  

Symbol, Chemistry.

1. didymium.

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DI ⁵ American  

1. Department of the Interior.

2. drill instructor.

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di- ⁶ American  

1. a prefix occurring in loanwords from Greek, where it meant “two,” “twice,” “double” (diphthong ); on this model, freely used in the formation of compound words (dicotyledon; dipolar ) and in chemical terms (diatomic; disulfide ).

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di- ⁷ American  

1. variant of dis- before b, d, l, m, n, r, s, v, and sometimes g and j: digest; divide.

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di- ⁸ American  

1. variant of dia- before a vowel.

   diorama.

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di. ⁹ American  

Or dia

abbreviation

1. diameter.

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di- ¹ British  

prefix

1. twice; two; double

   dicotyledon

2. 1. containing two specified atoms or groups of atoms

      dimethyl ether

      carbon dioxide

   2. a nontechnical equivalent of bi- 1

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DI ² British  

abbreviation

1. Defence Intelligence

2. Detective Inspector

3. Donor Insemination

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di- ³ British  

combining form

1. variant of dia-

   diopter

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Di ⁴ British  

symbol

1. didymium

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di– Scientific  

1. A prefix that means “two,” “twice,” or “double.” It is used commonly in chemistry, as in dioxide, a compound having two oxygen atoms.

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Etymology

Origin of di¹

< Italian < Latin dē

Origin of di²

Perhaps alteration of do ²

Origin of di-⁶

Middle English ≪ Latin < Greek, combining form representing dís twice, double, akin to dýo two. See bi- ¹, twi-

Example Sentences

See Examples For:

di Di DI di- di.

Far from the solemn pomp of the Vatican, nestled under the arcades of the mountain town of Santarcangelo di Romagna, a tailor clad all in black leaned over his sketch.

From Barron's ● Aug. 22, 2026

Additional support for science analysis from the Istituto Nazionale di Astrofisica in Italy; and the Centre National d'Études Spatiales in France is gratefully acknowledged.

From Science Daily ● Aug. 2, 2026

Pogacar has won almost every major race in the sport, including the Tour of Flanders, Giro d'Italia, Milan-San Remo, Road World Championships, Giro di Lombardia and Liege-Bastogne-Liege.

From BBC ● Jul. 26, 2026

Banca Monte dei Paschi di Siena is the biggest shareholder in Generali with a 13.3% stake, and has drawn takeover interest from Intesa Sanpaolo and Banco BPM.

From The Wall Street Journal ● Jul. 1, 2026

He had dark silky hair, pale skin, and dark clothes—my friend Nico di Angelo, the son of Hades.

From "The Last Olympian" by Rick Riordan

Others came up with captions including "Don't Look Up," a reference to the 2021 film starring Leonardo Di Caprio parodying societal apathy to the climate crisis.

From Barron's ● Jul. 29, 2026

Di Gioia brought it along when he went to see Big Boy 4014 in Altoona.

From The Wall Street Journal ● Jul. 21, 2026

"We're not in a drought situation yet, but at this rate, there's less than three weeks of water left in reserve," said Damiano Di Simine, an expert with environmental group Legambiente.

From Barron's ● Jun. 27, 2026

But fast forward five decades, and a similar seven-pass manoeuvre by Argentina against France in the 2022 final - finished by winger Angel Di Maria – took just 12 seconds.

From BBC ● Jun. 17, 2026

For the record, Estella had actually said, “Vete a buscar a Henry en el icehouse. Di, ‘Excuse me, I want to find a man named Henry.

From "Out of Darkness" by Ashley Hope Pérez

We’re presumed to be coldhearted tyrants who spend too much money on gear and private coaches and daydream about DI scholarships that will never come.

From The Wall Street Journal ● Aug. 20, 2026

Amari played DI Bascombe's son Adam Bascombe in Adolescence, Netflix's breakout hit of the year.

From BBC ● Mar. 19, 2026

JD Wyatt gives Poly 47-37 lead after three quarters of DI semifinal at Granada Hills.

From Los Angeles Times ● Feb. 27, 2025

It still needs to be ratified by the DI Board next week, but that is expected.

From Seattle Times ● Apr. 17, 2024

This extra width is called the lap, OC being the outside lap and DI the inside or exhaust lap.

From Steam Engines Machinery's Reference Series, Number 70 by Anonymous

"This relationship aligns with natural shifts in the color of ambient illumination, detectable during twilight by mammals with di- and tri-chromatic visual systems."

From Salon ● Nov. 8, 2023

NOTE.—The forms di- and dif- are euphonic forms of dis-; dif- is used before a root beginning with a vowel.

From New Word-Analysis by William Swinton

What about lecithin and mono-, di-, and triglycerides?

From "The Omnivore's Dilemma" by Michael Pollan

In the midafternoon, when the sun is high overhead—the earth’s equator close to the ball of burning fire, just like the di- agram in Understanding Our Universe—we turn onto the dirt road to Yana Urku.

From "The Queen of Water" by Laura Resau

Now let us consider a di- or bi-basic acid.

From The Chemistry of Hat Manufacturing Lectures Delivered Before the Hat Manufacturers' Association by Albert Shonk

Thomy ten. di. feod. in Bliston dict. feod.

From The Survey of Cornwall And an epistle concerning the excellencies of the English tongue by Richard Carew