Definition of dual in US English:



  • 1attributive Consisting of two parts, elements, or aspects.

    ‘their dual role at work and home’
    • ‘But Parkinson, a veteran of three title triumphs during the last two decades, has decided to step down altogether, leaving Lowe to perform a dual role this summer as Darwen prepare to defend their crown.’
    • ‘Now, can I turn to their arguments and address what seem to us to be their dual aspect?’
    • ‘A word must be said about the office of coroner, which too had something of a dual aspect.’
    • ‘His current role as executive chairman effectively combines the functions of chief executive and chairman, a dual role which is now frowned upon by institutions.’
    • ‘I like the notion of a library as a treasure chest, since it operates as a dual metaphor.’
    • ‘Most commonly, acute stabilization of patients with dual disorders refers to the management of physical, psychiatric, or drug toxicity crises.’
    • ‘Inexperienced nurses usually remain in orientation for an average of five months - longer if they are expected to function in a dual role.’
    • ‘From the beginning his relationship with her has got this dual element to it.’
    • ‘Foster parents should be willing to commute, be bilingual and have dual nationality.’
    • ‘Pavee's attacking sweeper played a dual role as a tough defender and made sleek wing attacks that resulted in major inroads into Big Players' defense.’
    • ‘The interesting aspect of this dual soundtrack is that each one presents a noticeably different version of the film.’
    • ‘Funding dual language immersion programs and transportation programs that shuttle students between school districts can also promote school integration.’
    • ‘You combine dual aspects by being ambitious professionally and domesticated in the home and family situations.’
    • ‘Hopefully, the elimination of the dual mandate will take care of that.’
    • ‘Gavin Hamilton and Gary Fellows have dual roles to play.’
    • ‘It was these dual aspects of perpetuity which were to assume such importance in America.’
    • ‘Byrne said he was hugely impressed by the pupils' enthusiasm and by the various demonstrations and said he was being pragmatic and playing a dual role on the day in hoping to recruit new students for the college.’
    • ‘These critics also recognize the dual aspects of decolonization.’
    • ‘Rather, he wanted to imitate a different aspect of Moshe: his dual role.’
    • ‘He wants to project that dual role.’
    double, twofold, binary
    View synonyms
    1. 1.1Grammar (in some languages) denoting an inflection that refers to exactly two people or things (as distinct from singular and plural)
      ‘Old English has dual number for first- and second-person pronouns’
      • ‘Yimas proper distinguishes four numbers in its pronominal paradigm (singular, dual, paucal, and plural) while Yimas Pidgin has only three.’
      • ‘Languages with dual markers have a different plural affix for sets of two than the affix for sets greater than two.’
      • ‘It has dual number, so nouns and verbs must be learned in singular, dual, and plural.’
    2. 1.2 (in an aircraft) using dual controls.
      ‘a dual flight’
      • ‘It would show the reaction of non flyers being taken on dual flights in incredible scenery.’
      • ‘Anyway, on this particular day I was scheduled for my fourth hour of dual instruction.’
      • ‘They arranged to give him a couple more hours of dual instruction.’
      • ‘Schedule periodic dual flights when the crosswind exceeds your comfort level.’
      • ‘You might want to consider scheduling an annual dual flight with an experienced instructor to review downwind take-offs and landings.’
  • 2often dual toMathematics
    (of a theorem, expression, etc.) related to another by the interchange of particular pairs of terms, such as “point” and “line.”.

    • ‘He had proved that compact abelian groups are dual to discrete abelian groups, and von Neumann was interested in extending this result.’


  • 1Grammar
    A dual form of a word.

    1. 1.1 The dual number.
  • 2Mathematics
    A theorem, expression, etc., that is dual to another.

    • ‘Because of the demands of differentiability in distribution theory, the spaces of test-functions and their duals are somewhat more complicated.’
    • ‘In fact this theorem is simply the dual of Pascal's theorem which was proved in 1639.’


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