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

The other bedrooms offer the same lavish touch and enough space for at least a queen-sized bed, while the bathrooms boast glass-enclosed showers, large soaking tubs, and dual vanities.

From MarketWatch • Apr. 14, 2026

Iqbal and Khan are both British nationals from Leyton, and the 17-year-old, who cannot be named for legal reasons, is a dual British and Pakistani national from Walthamstow.

From BBC • Apr. 13, 2026

But in “The Last Titans,” Mr. Vinen gives us an arresting dual portrait of human greatness.

From The Wall Street Journal • Apr. 13, 2026

He’s going through rehabilitation this week so he could be back for a dual meet and the Mt.

From Los Angeles Times • Apr. 13, 2026

I spend all my time enthusiastically telling her about my dual projects.

From "Finding Junie Kim" by Ellen Oh