plural of dual school

(dated) A mixed-sex school.

plural of dual-band

(graph theory) A graph derived from some plane graph in such a way that the derived graph has a vertex corresponding to each face of the given graph, an edge corresponding to each edge of the given graph that is shared by a pair of distinct faces, and a self-loop for each edge of the given graph that is a border of the same face on both of its sides.

(rail transport, of an electric train) Able to run using two different voltages, depending on the voltage supplied to the particular railway line, whether by third rail direct current or overhead wires.

(of a person, potentially offensive) Having mixed racial parentage or ancestry.

(education, psychology) Twice-exceptional.

plural of dual resident

(law, taxation) A person who is a resident for tax purposes in two or more countries.

(electrical engineering) Able to operate on two different electrical frequencies. / (radio communications) Able to receive and operate on two different radio frequencies.