Source : Webster's Revised Unabridged Dictionary (1913)

Allopathy \Al*lop"a*thy\, n. [Gr. ? other + ? suffering, ?, ?,
   to suffer: cf. G. allopathie, F. allopathie. See {Pathos}.]
   That system of medical practice which aims to combat disease
   by the use of remedies which produce effects different from
   those produced by the special disease treated; -- a term
   invented by Hahnemann to designate the ordinary practice, as
   opposed to {homeopathy}.

Source : WordNet®

allopathy
     n : the usual method of treating disease with remedies that
         produce effects differing from those produced by the
         disease itself [ant: {homeopathy}]