mirror image

from WordNet (r) 3.0 (2006)

mirror image
    n 1: a likeness in which left and right are reversed [syn:
         {mirror image}, {reflection}, {reflexion}]

from Moby Thesaurus II by Grady Ward, 1.0

25 Moby Thesaurus words for "mirror image":
      antipode, antipodes, antipole, antithesis, antonym, contra,
      converse, counter, counterbalance, countercheck, counterpoint,
      counterpoise, counterpole, counterterm, foil, inverse, obverse,
      offset, opposite, opposite number, reverse, setoff, the contrary,
      the other side, vis-a-vis