dual

American  

[doo-uhl, dyoo-] / ˈdu əl, ˈdju- /

adjective

1. of, relating to, or noting two.

2. composed or consisting of two people, items, parts, etc., together; twofold; double.

   dual ownership;

   dual controls on a plane.

3. having a twofold, or double, character or nature.

4. Grammar. being or pertaining to a member of the category of number, as in Old English, Old Russian, or Arabic, that denotes two of the things in question.

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noun

Grammar.

1. the dual number.

2. a form in the dual, as Old English git “you two,” as contrasted with ge “you” referring to three or more.

dual British  

/ ˈdjuːəl /

adjective

1. relating to or denoting two

2. twofold; double

3. (in the grammar of Old English, Ancient Greek, and certain other languages) denoting a form of a word indicating that exactly two referents are being referred to

4. maths logic (of structures or expressions) having the property that the interchange of certain pairs of terms, and usually the distribution of negation, yields equivalent structures or expressions

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noun

1. grammar

   1. the dual number

   2. a dual form of a word

verb

1. (tr) to make (a road) into a dual carriageway

Other Word Forms

• dually
  adverb

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Etymology

Origin of dual

First recorded in 1535–45; from Latin duālis “containing two, relating to a pair,” equivalent to du(o) two + -ālis -al ¹

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Explanation

Dual means double, or having two elements. If you have a dual major, it means you're majoring in two subjects, like astronomy and microbiology. The adjective dual comes from the Latin duo, for two, and means having two parts. You can have a dual purpose, following two goals at once. To copilot an airplane, you need a cockpit with dual controls. If you're sometimes nasty and sometimes sugar sweet, people might think you have a dual personality. Don't confuse dual, though, with duel, which is a fight between two people.

Example Sentences

See Examples For:

dual

The military aid package to the BIR, officials said, served the dual purpose of adding a new incentive for Cameroon to cooperate on accepting U.S. deportees while also supporting U.S. counterterrorism efforts in the region.

From The Wall Street Journal ● Oct. 29, 2026

They are lifted off the runway by a dual fuselage carrier plane to about 45,000 feet, where they separate, blast off to an altitude of 50 miles above earth and float back down.

From Los Angeles Times ● Oct. 29, 2026

Six other men remain on bail, one of them a dual UK-Iranian national who had been re-arrested last week.

From Barron's ● Oct. 27, 2026

The primary bathroom features dual vanities and a large soaking tub.

From MarketWatch ● Oct. 26, 2026

He acted as though he didn’t see me as I crept in as quietly as I could and squeezed my way into the dual desk bench I shared with Bright.

From "Flying Through Water" by Mamle Wolo

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