dual

adjective

1. 1

   Characterized by having two (usually equivalent) components.

   a dual-motor vehicle

2. 2

   Pertaining to two, pertaining to a pair of.

   dual engine failure

   dual citizenship

   Both Deborah and Samuel held dual roles as judges and prophets.

   And some Asian countries are tightening their immigration laws. Japan reinforced its strict stance in January when a court upheld the country’s ban against dual citizenship, rejecting a lawsuit filed by Japanese citizens living in Europe.

3. 3

   Pertaining to a grammatical number in certain languages that refers to two of something, such as a pair of shoes.

   Modern Arabic displays a dual number, as did Homeric Greek.

4. 4

   Exhibiting duality.

5. 5

   Being the space of all linear functionals of (some other space).

   Accordingly, a hyperplane in the sample space is dual to a subspace in the variable space.

6. 6

   Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.

   Every category is dual to its own dual, so if a statement holds in all categories so does its dual.

noun

1. 1

   Of an item that is one of a pair, the other item in the pair.

2. 2

   Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.

   The octahedron is the dual of the cube. The icosahedron is the dual of the dodecahedron.

3. 3

   The dual number.

4. 4

   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.

5. 5

   A head-to-head match or meet between two teams, such as two high schools or colleges.

   Wrestling duals and meets take place at the Wisconsin Field House. There are no advance single event ticket sales.

   But Dave agreed to participate in the Bulgarian dual, and that trapped me into having to wrestle, too.

   Early in 2021, she became the first female to compete and win a match at the Ter-Hark Cup wrestling dual, helping her squad to victory.

verb

1. 1

   To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.

   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.

   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.

   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.

Forms

plural

duals

past tense

dualed, dualled

past participle

dualed, dualled

present participle

dualing, dualling

third person singular

duals