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  

combining form

1. variant of dia-

   diopter

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Di ² British  

symbol

1. didymium

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di- ³ 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 ⁴ British  

abbreviation

1. Defence Intelligence

2. Detective Inspector

3. Donor Insemination

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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

The company’s future was very much in doubt when it found a savior in Enzo’s one-time protégé, Luca di Montezemolo, a blue-eyed Italian aristocrat with the steady hand to pull off a U-turn at Ferrari.

From The Wall Street Journal • Apr. 10, 2026

“Elevated yields put pressure on equity valuations, particularly in growth sectors such as technology,” said Antonio di Giacomo, senior market analyst at multi-asset broker XS.com.

From Barron's • Mar. 25, 2026

Researchers from the University of Padua, Politecnico di Milano, and the CNR Institute for Photonics and Nanotechnologies have demonstrated a new approach using an unexpected material: borosilicate glass.

From Science Daily • Mar. 24, 2026

Roles outside of the Queen of the Night included the title role in “Lucia di Lammermoor,” the princess in “The Snow Queen,” Zerlina in “Don Giovanni” and Pat Nixon in “Nixon in China.”

From Los Angeles Times • Mar. 18, 2026

As usual, di Angelo was perched atop the foremast.

From "The House of Hades" by Rick Riordan