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  

combining form

1. variant of dia-

   diopter

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Di ³ British  

symbol

1. didymium

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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

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

Milan's Santagiulia Arena will be the setting for the para ice hockey, while para biathlon and para cross-country skiing events will take place in Val di Fiemme.

From Barron's • Mar. 6, 2026

The opening ceremony took place at the Arena di Verona, a 2,000-year-old amphitheatre and Unesco world heritage site, despite no competitions taking place in the city.

From BBC • Mar. 6, 2026

Suddenly where Nico di Angelo had been standing was a potted plant about five feet tall, with drooping green leaves, tufts of silk, and half a dozen ripe yellow ears of corn.

From "The House of Hades" by Rick Riordan