Definitions
1.AdjectiveCharacterized by having two (usually equivalent) components."a dual-motor vehicle"
2.AdjectivePertaining to two, pertaining to a pair of."dual engine failure; dual citizenship"
3.AdjectivePertaining 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.AdjectiveExhibiting duality.
5.AdjectiveBeing the space of all linear functionals of (some other space).
6.AdjectiveBeing the dual of some other category; containing the same objects but with source and target reversed for all morphisms.
7.NounOf an item that is one of a pair, the other item in the pair.
8.NounOf 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."
9.NounThe dual number.
10.NounOf 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.
11.NounA head-to-head match or meet between two teams, such as two high schools or colleges.
12.VerbTo convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.