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

The dual quakes left a path of destruction from Caracas, the capital, to the coast and elsewhere.

From Los Angeles Times • Jun. 27, 2026

Propulsion All electric, with dual AC synchronous motors, 88 kWh, 400V lithium-ion battery pack, rear-biased, multi-mode/terrain all-wheel drive.

From The Wall Street Journal • Jun. 27, 2026

“Americans are falling in love with Vietnam and its dual communist–capitalist system of government and economics,” some guy in Hanoi could have said after I gushed to him about how much fun I was having.

From Slate • Jun. 25, 2026

De la Espriella, a dual US-Colombian national who calls himself "The Tiger," won May's first-round vote promising to wage war on groups who refused to sign the accord.

From Barron's • Jun. 21, 2026

“The Italian stallion,” he chorded, a dual reference to the heritage of our new neighbor, Marcellus DiAngelo, and his obsession with physical fitness.

From "Red Kayak" by Priscilla Cummings