The Collaborative International Dictionary of English v.0.48:

Carnage \Car"nage\, n. [F. carnage, LL. carnaticum tribute of
   animals, flesh of animals, fr. L. caro, carnis, flesh. See
   Carnal.]
   1. Flesh of slain animals or men.
      [1913 Webster]

            A miltitude of dogs came to feast on the carnage.
                                                  --Macaulay.
      [1913 Webster]

   2. Great destruction of life, as in battle; bloodshed;
      slaughter; massacre; murder; havoc.
      [1913 Webster]

            The more fearful carnage of the Bloody Circuit.
                                                  --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

carnage
    n 1: the savage and excessive killing of many people [syn:
         slaughter, massacre, mass murder, carnage,
         butchery]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "carnage":
   bloodbath, bloodshed, blue ruin, breakup, butchery, consumption,
   damnation, decimation, depredation, desolation, despoilment,
   despoliation, destruction, devastation, disintegration,
   disorganization, disruption, dissolution, final solution, genocide,
   havoc, hecatomb, holocaust, killing, mass destruction, mass murder,
   massacre, perdition, pogrom, race extermination, race-murder,
   ravage, ruin, ruination, saturnalia of blood, shambles, slaughter,
   spoliation, undoing, vandalism, waste, wholesale murder, wrack,
   wrack and ruin, wreck