List of two synonyms and two related words.
biform, bifurcated, bilateral, bipartisan, bipartite, both, brace, couple, couplet, dichotomous, distich, double, double harness, doublet, duad, duadic, dual, dualistic, duet, duo, duplex, duplicated, dyad, dyadic, identical, match, matched, mates, pair, set of two, span, team, the two, twain, twin, twinned, two-sided, twosome, yoke