dual

 
Pronunciation: /ˈdjuːəl/

adjective

  • 1 [attributive] consisting of two parts, elements, or aspects: their dual role at work and home dual-language texts in English and Italian
  • Grammar (in some languages) denoting an inflection that refers to exactly two people or things (as distinct from singular and plural).
  • (in an aircraft) using dual controls: a dual flight
  • 2 (often dual to) Mathematics (of a theorem, expression, etc.) related to another by the interchange of particular pairs of terms, such as ‘point’ and ‘line’.

noun

  • 1 Grammar a dual form of a word.
  • [mass noun] the dual number.
  • 2 Mathematics a theorem, expression, etc., that is dual to another.

verb (duals, dualling, dualled)

[with object] British
  • convert (a road) into a dual carriageway: though there are no plans to dual the road, a public consultation on the A64 is set to start before the end of the year

Derivatives

dualize

(also dualise) verb

dually

adverb

Origin:

late Middle English (as a noun denoting either of the two middle incisor teeth in each jaw): from Latin dualis, from duo 'two'

Do not confuse dual with duel. Dual means 'having two parts or aspects' ( the dual role of proprietor/manager), whereas duel means 'a fight or contest between two people' ( he challenged me to a duel).