1. Of or pertaining to two. dual number (Gram.), the inflected form expressing two or a pair.
1607 BP. ANDREWES Serm. II. 217 In the holy tongue, the word which signifieth life is of the dual number.
J. PARKER Paracl. II. Epil. 397 The great dual law which makes
Adam and Eve one humanity, the dry land and the seas one globe.
1654 H. L'ESTRANGE Chas. I (1655) 7 His Majesty..conducted her to Canterbury, where the marriage was finally completed..From Canterbury his now dual Majesty took coach for White-hall.
TYNDALL Fragm. Sc. (1879) II. vi. 79 Truth is often of a dual
The condition or fact of being dual, or consisting of two parts,
natures, etc.; twofold condition.
1892 WESTCOTT Gospel of Life 176 Zarathustra himself seems to have taught a certain duality in the one Divine Being.