From WordNet (r) 3.0 (2006): duad n 1: two items of the same kind [syn: couple, pair, twosome, twain, brace, span, yoke, couplet, distich, duo, duet, dyad, duad]
duad n 1: two items of the same kind [syn: couple, pair, twosome, twain, brace, span, yoke, couplet, distich, duo, duet, dyad, duad]