Source : WordNet®

twosome
     n 1: two items of the same kind [syn: {couple}, {pair}, {twain},
          {brace}, {span}, {yoke}, {couplet}, {distich}, {duo}, {duet},
           {dyad}, {duad}]
     2: a pair who associate with one another; "the engaged couple";
        "an inseparable twosome" [syn: {couple}, {duo}, {duet}]