dua

a. [ L. dualis, fr. duo two. See Two. ] Expressing, or consisting of, the number two; belonging to two; as, the dual number of nouns, etc. , in Greek. [ 1913 Webster ]

Here you have one half of our dual truth. Tyndall. [ 1913 Webster ]

n. (Chem.) An explosive substance consisting essentially of sawdust or wood pulp, saturated with nitroglycerin and other similar nitro compounds. It is inferior to dynamite, and is more liable to explosion. [ 1913 Webster ]

n. [ Cf. F. dualisme. ] State of being dual or twofold; a twofold division; any system which is founded on a double principle, or a twofold distinction; as: (a) (Philos.) A view of man as constituted of two original and independent elements, as matter and spirit. (Theol.) (b) A system which accepts two gods, or two original principles, one good and the other evil. (c) 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. (d) (Physiol.) The theory that each cerebral hemisphere acts independently of the other. [ 1913 Webster ]

An inevitable dualism bisects nature, so that each thing is a half, and suggests another thing to make it whole. Emerson. [ 1913 Webster ]

n. [ Cf. F. dualiste. ] 1. One who believes in dualism; a ditheist. [ 1913 Webster ]

2. One who administers two offices. Fuller. [ 1913 Webster ]

a. Consisting of two; pertaining to dualism or duality. [ 1913 Webster ]

Dualistic system or
Dualistic theory (Chem.), an old theory, originated by Lavoisier and developed by Berzelius, that all definite compounds are binary in their nature, and consist of two distinct constituents, themselves simple or complex, and possessed of opposite chemical or electrical affinities; -- superseded by later developments in chemical bonding theory, especially quantum mechanics. [ 1913 Webster +PJC ]

n. [ L. dualitas: cf. F. dualité. ] The quality or condition of being two or twofold; dual character or usage. [ 1913 Webster ]

n. [ Gael. & Ir. ] A division of a poem corresponding to a canto; a poem or song. [ R. ] [ 1913 Webster ]