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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  

abbreviation

1. Defence Intelligence

2. Detective Inspector

3. Donor Insemination

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di- ² British  

combining form

1. variant of dia-

   diopter

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Di ³ British  

symbol

1. didymium

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di- ⁴ 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– 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.

Find insight on bitcoin, Intesa’s bid for Banca Monte dei Paschi di Siena and more in the latest Market Talks covering Financial Services.

From The Wall Street Journal ● Oct. 5, 2026

“I think the Paramount deal is definitely front and center,” said Tom di Galoma, a managing director at Mischler Financial Group, as the 10-year yield rose 5 basis points in afternoon trading.

From MarketWatch ● Sep. 30, 2026

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

Amongst those criticising the car were Italy's deputy prime minister Matteo Salvini and former Ferrari chairman Luca Cordero di Montezemolo, who said the car was "risking the destruction of a legend".

From BBC ● Aug. 17, 2026

Sure, he hoped di Angelo was okay, but he had headaches of his own.

From "The House of Hades" by Rick Riordan

Electric vehicles can also accelerate and decelerate much more quickly than conventional combustion cars, which Di Giulio says can cause motion sickness.

From BBC ● Oct. 3, 2026

One person hoping to see a cheaper more transparent market for vet services is Clive Di Giorgio, who got in touch with BBC Your Voice.

From BBC ● Sep. 21, 2026

Sandwiched between was a massive new work, “Invisible House,” co-commissioned by this orchestra and the conductor’s former one, composed by a not especially famous Canadian, Zosha Di Castri, a music professor at Columbia University.

From The Wall Street Journal ● Sep. 17, 2026

It’s a Taoist temple where people come to worship Guan Di, a deified Chinese general revered as the god of commerce and war.

From The Wall Street Journal ● Sep. 6, 2026

"What’s going on here, Ari? A ver. Di me."

From "Aristotle and Dante Discover the Secrets of the Universe" by Benjamin Alire Saenz

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

DI Collins appealed for anyone with information to contact the police.

From BBC ● Jun. 19, 2026

El Camino Real holds on for 37-36 win over Eagle Rock in City DI girls semifinal.

From Los Angeles Times ● Feb. 22, 2026

The DI Council also moved forward on legislation that would allow schools to be more actively involved in securing sponsorship deals for their athletes.

From Seattle Times ● Apr. 17, 2024

Now the rectangle gDC is to the square of DI as the square of CG is to the square of CM; hence DI or CE will be 98,353.

From Treatise on Light by Christiaan Huygens

"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

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

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

From "The Omnivore's Dilemma" by Michael Pollan

The word "dihedral" is from the Greek, di- meaning "two," and hedra meaning "seat."

From The Teaching of Geometry by David Eugene Smith

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