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

“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

For years, Randall told anyone who would listen, “I am picturing us dancing on a rooftop in Val di Fiemme celebrating a men’s relay medal.”

From The Wall Street Journal • Feb. 19, 2026

Czech ski jumper Klara Ulrichova in action at Val di Fiemme.

From BBC • Feb. 9, 2026

He still had to save Nico di Angelo, assuming the guy wasn’t already dead.

From "The Mark of Athena" by Rick Riordan