| Dyad 1. (n.) Two units treated as one; a couple; a pair. 2. (n.) An element, atom, or radical having a valence or combining power of two. 3. (a.) Having a valence or combining power of two; capable of being substituted for, combined with, or replaced by, two atoms of hydrogen; as, oxygen and calcium are dyad elements. See Valence. Thesaurus Entries both, brace, couple, couplet, distich, double harness, doublet, duad, duet, duo, match, mates, pair, set of two, span, team, the two, twain, two, twosome, yoke |