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

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

See Examples For:

dual

The Fed has a dual mandate to keep inflation to its long-term target while ensuring maximum employment in the world's largest economy.

From Barron's ● Jul. 28, 2026

The framework, which simplifies dual IPOs and secondary listings while expanding cross-border investment products, could broaden Bursa’s IPO pipeline by giving issuers access to both Malaysian and Hong Kong investors, she says.

From The Wall Street Journal ● Jul. 27, 2026

What forged McElwee’s passion and helped him establish his life’s work now reveals its dual nature as the wedge that kept him and Adrian apart.

From Salon ● Jul. 24, 2026

They included legislative educational additions such as ethnic studies and financial literacy, a statewide push into college and career pathways, and the expansion of dual enrollment with community colleges.

From Los Angeles Times ● Jul. 23, 2026

The dual embarrassments would have the mutually reinforcing effect of reorienting Ernest and his laboratory toward much more careful research.

From "Big Science" by Michael Hiltzik