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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

See Examples For:

duo duos

To choose their first country, the duo spun a digital wheel, landed on Armenia and found themselves at Little Armenia Cafe in Greenpoint, Brooklyn, the very next night.

From The Wall Street Journal ● Aug. 16, 2026

In 2002, Hodgden and original guitarist Achim “Dange” St. Dangerfield started the band as an acoustic duo doing cover songs.

From Los Angeles Times ● Aug. 13, 2026

Oates, 78, who is best known as one half of the musical duo Hall & Oates, initially listed his 4.3-acre spread—which is located in Woody Creek, just outside of Aspen—for $6 million in 2017.

From MarketWatch ● Aug. 12, 2026

The duo layer backing tracks until they seemingly collapse, like the dueling accenting rhythms of “Soledad” or the spacey and spectacular “Sensación,” which reaches a level of yearning that Emerald Fennell’s “Wuthering Heights” couldn’t buy.

From Los Angeles Times ● Aug. 11, 2026

No one had ever heard of these avatars before, but their names seemed to indicate they were working together, either as a duo or as part of a clan.

From "Ready Player One: A Novel" by Ernest Cline

These giant black hole duos are expected to form naturally after galaxies merge.

From Science Daily ● Jun. 5, 2026

Now, 43 years later, Russell and Hawn have become one of Hollywood’s most-loved duos and have turned their focus to real estate.

From MarketWatch ● Mar. 26, 2026

Mr. Millepied’s contemporary dance choreography is dominated by animated groups alternating with trios, duos and solos.

From The Wall Street Journal ● Mar. 9, 2026

Following Monday's rhythm dance, the duos return to the ice on Wednesday night for the free dance.

From BBC ● Feb. 11, 2026

Or like Pa’s old doo-wop records with duos and trios that went high, higher, then low.

From "Gone Crazy in Alabama" by Rita Williams-Garcia

Related Words

• pair