OXFORD DICTIONARY
dual, adj., n., & v.
--adj.
1 of two; twofold.
2 divided in two; double (dual ownership).
3 Gram. (in some languages) denoting two persons or things (additional to singular and plural).
--n. (also dual number) Gram. a dual form of a noun, verb, etc.
--v.tr. (dualled, dualling) Brit. convert (a road) into a dual carriageway.
dual carriageway Brit. a road with a dividing strip between the traffic in opposite directions. dual control (of a vehicle or an aircraft) having two sets of controls, one of which is used by the instructor. dual in-line package Computing see DIP. dual-purpose (of a vehicle) usable for passengers or goods.
duality n. dualize v.tr. (also -ise). dually adv.
L dualis f. duo two
THESAURUS
dual
Janus-like, ambidextrous, bifacial, bifold, biform, bifurcated, bilateral, binary, binate, biparous, bipartisan, bipartite, bivalent, conduplicate, dichotomous, disomatous, double, double-barreled, double-faced, duadic, dualistic, duple, duplex, duplicate, duplicated, dyadic, geminate, geminated, identical, matched, paired, second, secondary, twain, twin, twinned, two, two-faced, two-level, two-ply, two-sided, two-story, twofold
ROGET THESAURUS
dual
Duality
N
duality, dualism, duplicity, biplicity, biformity, polarity, two, deuce, couple, duet, brace, pair, cheeks, twins, Castor and Pollux, gemini, Siamese twins, fellows, yoke, conjugation, dispermy, doublets, dyad, span, two, twin,
dual, dualistic, double, binary, binomial, twin, biparous, dyadic, conduplicate, duplex, biduous, binate, diphyletic, dispermic, unijugate, tete-a-tete, coupled, conjugate, both, both the one and the other.