dual

dual — adjective

1. having or consisting of two separate parts, functions, or aspects that work toge

1.adjectiveB1
Definition

having or consisting of two separate parts, functions, or aspects that work together as one — for example, a kitchen tool that both chops and grinds, or a manager who also handles customer service.

Example

Chiara bought a sofa with a dual function — it folds out into a bed.

dual function / dual purpose

The new phone has a dual camera that takes wide and close-up shots.

Common collocations
  • dual role
  • dual purpose
  • dual function
  • dual system
  • dual approach
  • dual membership
Synonyms
  • double

    more general; 'double' means twice as much, while 'dual' stresses two coordinated parts

  • twin

    stronger emphasis on matched pairs (twin beds, twin engines)

  • twofold

    more formal; used for abstract aspects rather than physical parts

Antonyms
  • single

    having only one part or function

Grammar Patterns

dual + noun

Usage Note

Only used before a noun. Cannot follow linking verbs (e.g. not 'the role is dual').

Common Mistakes

The car has a dual engine' (meaning two separate engines).
The car has a dual-fuel engine.
'dual' describes one item that combines two features, not two separate items.

2. referring to a car or van that has two identical sets of driving controls — the

2.adjectiveB2
Definition

referring to a car or van that has two identical sets of driving controls — the learner operates the main set while the instructor can use the second set to intervene when necessary.

Example

Driving school cars have dual controls so the instructor can brake from the passenger side.

dual controls in a learner vehicle

Quan passed his test quickly because he practised in a car with dual controls.

Common collocations
  • dual controls
  • dual-control car
  • dual pedals
  • dual-control vehicle

Grammar Patterns

dual-control + noun

dual + controls/pedals/brakes

Usage Note

Almost always appears before 'controls', 'pedals', or 'brakes'. The compound form 'dual-control' (with a hyphen) is common before other nouns like 'car' or 'vehicle'.

3. having the legal right to be recognised as a citizen of two nations simultaneous

3.adjectiveB2
Definition

having the legal right to be recognised as a citizen of two nations simultaneously, carrying the privileges and duties of each.

Example

Bilal holds dual citizenship in Canada and Lebanon through his parents.

dual citizenship / dual nationality

Some countries, such as Japan, do not let citizens hold dual nationality after age twenty.

Common collocations
  • dual citizenship
  • dual nationality
  • dual passport
Antonyms

Grammar Patterns

dual + citizenship/nationality

Usage Note

Used exclusively with nouns meaning citizenship or nationality. Not used for other kinds of double belonging (e.g. not 'dual club membership' in this sense).

dual — verb

dual — noun

Word family

  • duality
    nounB2
  • dualism
    nounC1
  • dualist
    nounC1
  • dualistic
    adjectiveC1
  • dually
    adverbC1

Synonym discussion

Sense: adjective/1

'Dual' and 'double' are the closest pair, but they differ in focus: 'double' simply means twice the amount or size (double the price, double portion), while 'dual' stresses two coordinated parts functioning as a unit (dual role, dual purpose). 'Twin' implies two identical or matching items (twin beds, twin towers) — a stronger emphasis on symmetry than 'dual' carries. 'Twofold' is more formal and used for abstract aspects (a twofold increase, a twofold purpose) rather than physical parts. 'Binary' is limited to systems of exactly two states (binary code, binary choice) and is a technical term in computing and classification. For a learner describing a device that does two things, 'dual' is the best choice — a dual-function appliance, not a double-function one.

double ↗twin ↗twofold ↗binary ↗

Common collocations

Nouns

Phrases

  • dual role as
  • dual purpose of
  • dual function of

Prepositions

  • dual in + noun

Etymology

LatinEnglish

Comes from Latin 'duālis', meaning 'that contains two', which is built from 'duo' ('two'). The word first appeared in English in the early 1600s as a grammatical term for the dual number, and over time its use expanded to general descriptions of anything having two parts or aspects.