[ doo-oh, dyoo-oh ]
/ ˈdu oʊ, ˈdyu oʊ /
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noun, plural du·os.
Music. duet.
two persons commonly associated with each other; couple.
two animals or objects of the same sort; two things ordinarily placed or found together; a pair: a duo of lovebirds.
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Question 1 of 7
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Origin of duo

1580–90; <Italian <Latin: two

Other definitions for duo (2 of 2)


a combining form meaning “two,” used in the formation of compound words: duologue.

Origin of duo-

Combining form of Greek dýo,Latin duotwo
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does duo- mean?

Duo- is a combining form used like a prefix meaning “two.” It is occasionally used in technical terms.

Duo- comes from Greek dýo and Latin duo, both meaning “two.” In fact, English’s own word two is related to these roots! Learn more at our entry at two.

Examples of duo-

One example of a technical term that features the combining form duo- is duotone, “of two tones or colors.”

The combining form duo- means “two,” while -tone here means “color.” Duotone literally translates to “two colors” or “two-colored.”

What are some words that use the combining form duo-?

What are some other forms that duo- may be commonly confused with?

The combining form duodeno- does not use duo- to mean “two.” Learn why duodeno- represents a part of the small intestine at our entry.

Break it down!

A monologue is the part of a drama in which a single speaker talks at length. With this in mind, what is a duologue, also known as a dialogue?

How to use duo in a sentence

British Dictionary definitions for duo (1 of 2)

/ (ˈdjuːəʊ) /

noun plural duos or dui (ˈdjuːiː)
  1. a pair of performers
  2. another word for duet
a pair of actors, entertainers, etc
informal a pair of closely connected individuals

Word Origin for duo

C16: via Italian from Latin: two

British Dictionary definitions for duo (2 of 2)


combining form
indicating twoduotone

Word Origin for duo-

from Latin
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