dual
/ˈdul/ adjective, noun, verb
Forms duals dualing dualling dualed dualled du.
- adjective Characterized by having two (usually equivalent) components. “a dual-motor vehicle”
- adjective Pertaining to two, pertaining to a pair of. “dual engine failure”
- adjective (grammar) 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.”
- adjective (mathematics, physics) Exhibiting duality.
- adjective (linear algebra) Being the space of all linear functionals of (some other space).
- adjective (category theory) Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.
- noun Of an item that is one of a pair, the other item in the pair.
- noun (geometry) 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.”
- noun (grammar) The dual number.
- noun (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.
- noun (wrestling) A head-to-head match or meet between two teams, such as two high schools or colleges.
- verb (transitive) To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.
Synonyms
double twin duplicate duplex duple twissel twofold twosome opposite binary two-fold treble threefold three-fold
Etymology
Borrowed from Latin dualis (“two”), from duo (“two”) + adjective suffix -alis.
Webster’s 1913
- adjective Expressing, or consisting of, the number two; belonging to two; as, the dual number of nouns, etc. , in Greek.
Etymology [L. dualis, fr. duo two. See Two.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “dual”, CC BY-SA 4.0. Details