both, brace, couple, couplet, distich, double harness, doublet, duad, duet, duettino, dyad, ensemble music, ensemble singing, match, mates, octet, pair, part music, part singing, part song, polyphonic music, quartet, quintet, septet, septuor, sestet, set of two, sextet, span, team, terzet, terzetto, the two, trio, twain, two, twosome, yoke