Definition of "dual"

dual

/ˈdjuː.əl/

adjective
not comparable
1. Characterized by having two (usually equivalent) components.
2. Pertaining to two, pertaining to a pair of.
  Quotations
  Both Deborah and Samuel held dual roles as judges and prophets.
  2020, Grace Ying May, “Women Disciplining Men: A Biblical Pattern of Leadership”, in Aída Besançon Spencer, William David Spencer, editors, Christian Egalitarian Leadership: Empowering the Whole Church According to the Scriptures, page 48
3. (grammar) Pertaining to a grammatical number in certain languages that refers to two of something, such as a pair of shoes.
4. (mathematics, physics) Exhibiting duality.
5. (linear algebra) Being the space of all linear functionals of (some other space).
  Quotations
  Accordingly, a hyperplane in the sample space is dual to a subspace in the variable space.
  2012, Doug Fisher, Hans-J. Lenz, Learning from Data: Artificial Intelligence and Statistics V, Springer Science & Business Media, page 81
6. (category theory) Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.
  Quotations
  Every category is dual to its own dual, so if a statement holds in all categories so does its dual.
  1992, Colin McLarty, Elementary Categories, Elementary Toposes, Clarendon Press, page 77
noun
plural duals
1. Of an item that is one of a pair, the other item in the pair.
2. (geometry) Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.
3. (grammar) The dual number.
4. (mathematics) Of a vector in an inner product space, the linear functional corresponding to taking the inner product with that vector. The set of all duals is a vector space called the dual space.
verb
third-person singular simple present duals, present participle (UK) dualling or (US) dualing, simple past and past participle (UK) dualled or (US) dualed
1. (transitive) To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.
  Quotations
  I have to declare an interest and I do so with some ambivalence because if the road is dualled it is likely to take half of my front garden.
  1994, Great Britain. Parliament. House of Commons, Parliamentary Debates
  The power generation and propulsion systems are dualled to accommodate component failure and maintain propulsion at reduced speed should any part of one system be lost.
  2006, David Lowe, Intermodal Freight Transport, page 163
  The investment will allow Nexus to increase service frequencies, reduce journey times, and improve reliability by dualling three sections of line between Pelaw and South Shields.
  2021 September 22, “Network News: Nexus increases Tyne and Wear Metro train order to 46”, in RAIL, number 940, page 23

Definition of "dual"

dual

adjective

Quotations

Quotations

Quotations

noun

verb

Quotations