dual

Dual means double, or having two elements. If you have a dual major, it means you're majoring in two subjects, like astronomy and microbiology.

The adjective dual comes from the Latin duo, for two, and means having two parts. You can have a dual purpose, following two goals at once. To copilot an airplane, you need a cockpit with dual controls. If you're sometimes nasty and sometimes sugar sweet, people might think you have a dual personality. Don't confuse dual, though, with duel, which is a fight between two people.

Definitions of dual
1

adj consisting of or involving two parts or components usually in pairs

dual controls for pilot and copilot”
Synonyms:
double, duple
multiple
having or involving or consisting of more than one part or entity or individual

adj having more than one decidedly dissimilar aspects or qualities

Synonyms:
double, three-fold, threefold, treble, two-fold, twofold
multiple
having or involving or consisting of more than one part or entity or individual

adj a grammatical number category referring to two items or units as opposed to one item (singular) or more than two items (plural)

“ancient Greek had the dual form but it has merged with the plural form in modern Greek”
Synonyms:
plural
grammatical number category referring to two or more items or units