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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.


di 2 American  
[dee] / di /

noun

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


Di 3 American  
[dahy] / daɪ /

noun

  1. a female given name, form of Diana.


Di 4 American  
Symbol, Chemistry.
  1. didymium.


DI 5 American  
  1. Department of the Interior.

  2. drill instructor.


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 ).


di- 7 American  
  1. variant of dis- before b, d, l, m, n, r, s, v, and sometimes g and j: digest; divide.


di- 8 American  
  1. variant of dia- before a vowel.

    diorama.


di. 9 American  
Or dia

abbreviation

  1. diameter.


di- 1 British  

combining form

  1. variant of dia-

    diopter

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Di 2 British  

symbol

  1. didymium

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

di- 3 British  

prefix

  1. twice; two; double

    dicotyledon

    1. containing two specified atoms or groups of atoms

      dimethyl ether

      carbon dioxide

    2. a nontechnical equivalent of bi- 1

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

DI 4 British  

abbreviation

  1. Defence Intelligence

  2. Detective Inspector

  3. Donor Insemination

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.


Etymology

Origin of di1

< Italian < Latin

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

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Still, Luca di Montezemolo, Ferrari’s former chairman, told reporters on Tuesday that the automaker is “risking the destruction of a legend.”

From Los Angeles Times • May 27, 2026

Harding, 50, who currently serves as director of Italy's Accademia Nazionale di Santa Cecilia, will make his Los Angeles debut in the 2027/2028 season.

From Barron's • May 26, 2026

Legendary Argentina World Cup winner Angel di Maria has blamed his unhappy spell at Manchester United on former boss Louis van Gaal.

From BBC • May 26, 2026

“I think we are in for a bit of a rocky road,” di Galoma said.

From MarketWatch • May 18, 2026

“Why would the good Abbot Hubert have wicked Michelangelo di Bologna as his prior?”

From "The Inquisitor's Tale" by Adam Gidwitz

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