dual

American  

[doo-uhl, dyoo-] / ˈdu əl, ˈdyu- /

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

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

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

Sangha, a dual US-UK citizen who has been in federal custody since 2024, has reportedly apologised to Perry's family.

From BBC • Apr. 8, 2026

His dual nationality and peripatetic, bi-cultural upbringing, combined with travel grants in 1927 and 1949 that took him all over Europe, Asia and North Africa, produced arguably the most cosmopolitan artist of his generation.

From The Wall Street Journal • Apr. 8, 2026

Ackman last month filed for a dual initial public offering of his management company and an investment fund on the New York Stock Exchange.

From Barron's • Apr. 7, 2026

The entirety of the 10th floor is occupied by the palatial primary suite, which features its own spa-style bathroom, a sauna, a workout room, dual dressing rooms, as well as a private terrace.

From MarketWatch • Apr. 6, 2026

Had my dual obsessions with the egg and Art3mis finally driven me completely insane?

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