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• duo
  duo

  noun

  duet.
• duo-
  duo-

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

duo

¹ American  

[doo-oh, dyoo-oh] / ˈdu oʊ, ˈdju oʊ /

noun

duos plural

1. Music. duet.

2. two persons commonly associated with each other; couple.

3. 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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duo- ² American  

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

   duologue.

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duo ¹ British  

/ ˈdjuːəʊ /

noun

1. music

   1. a pair of performers

   2. another word for duet

2. a pair of actors, entertainers, etc

3. informal a pair of closely connected individuals

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duo- ² British  

combining form

1. indicating two

   duotone

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Usage

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.

Other Word Forms

Noun Inflected Forms

• duos
  plural

Etymology

Origin of duo¹

1580–90; < Italian < Latin: two

Origin of duo-²

Combining form of Greek dýo, Latin duo two

Compare meaning

How does duo compare to similar and commonly confused words? Explore the most common comparisons:

• duo vs. duet

Explanation

A duo is a pair of things or people. Batman and Robin are a famous dynamic duo, but a duo is any two people doing something together, not just crime fighting. In fact, a duo usually entertains. You can complain that you can't find a duo of matching socks, but it's more common to use duo for people who perform together. For example, Penn and Teller are a magician duo, and Laurel and Hardy were a comedy duo. If you and your sister play your ukuleles together in the subway for tips, you're also a duo. Originally, a duo was a song written for two voices, from the Latin meaning of duo, "two."

Example Sentences

Poly is in Pool C and the duo gets to take on receivers from Capistrano Valley, San Diego Lincoln, Servite and Santa Margarita.

From Los Angeles Times • Jul. 5, 2026

My classmates included owners of nearby summer homes, city folk looking for a weekend away and more than one father-son duo.

From The Wall Street Journal • Jul. 5, 2026

Still, the duo had full faith that the bones of the dwelling would allow them to create their perfect countryside retreat.

From MarketWatch • Jul. 2, 2026

That is more than any other duo on record since 1966 in the competition.

From BBC • Jul. 1, 2026

They were a dynamic duo, and Seven looked forward to her and Poppy following in their footsteps.

From "Witchlings" by Claribel A. Ortega

Related Words

• pair