dual

The definition of dual is something that has to do with two or two parts.

(adjective)

An example of something dual is an electric toothbrush that both rotates and moves from side-to-side while it brushes your teeth; dual movement.
An example of something dual is a plan of attack that has two parts; dual plan of attack.

See dual in Webster's New World College Dictionary

adjective

of two
having or composed of two parts or kinds, like or unlike; double; twofold: a dual nature

Origin: L dualis < duo, two

noun

Related Forms:

See dual in American Heritage Dictionary 4

adjective

Composed of two usually like or complementary parts; double: dual controls for pilot and copilot; a car with dual exhaust pipes.
Having a double character or purpose: a belief in the dual nature of reality.
Grammar Of, relating to, or being a number category that indicates two persons or things, as in Greek, Sanskrit, and Old English.

noun
Grammar