n. - State of being dual or twofold; a twofold division; any system which is founded on a double principle, or a twofold distinction
n. - A view of man as constituted of two original and independent elements, as matter and spirit.
n. - A system which accepts two gods, or two original principles, one good and the other evil.
n. - The doctrine that all mankind are divided by the arbitrary decree of God, and in his eternal foreknowledge, into two classes, the elect and the reprobate.
n. - The theory that each cerebral hemisphere acts independently of the other.