The Collaborative International Dictionary of English v.0.48:

Prophecy \Proph"e*cy\, n.; pl. Prophecies, [OE. prophecie, OF.
   profecie, F. proph['e]tie, L. prophetia, fr. Gr. ?, fr. ? to
   be an interpreter of the gods, to prophesy, fr. ? prophet.
   See Prophet.]
   1. A declaration of something to come; a foretelling; a
      prediction; esp., an inspired foretelling.
      [1913 Webster]

            He hearkens after prophecies and dreams. --Shak.
      [1913 Webster]

            Prophecy came not in old time by the will of man.
                                                  --2. Pet. i.
                                                  21.
      [1913 Webster]

   2. (Script.) A book of prophecies; a history; as, the
      prophecy of Ahijah. --2 Chron. ix. 29.
      [1913 Webster]

   3. Public interpretation of Scripture; preaching; exhortation
      or instruction.
      [1913 Webster]

WordNet (r) 3.0 (2006):

prophecy
    n 1: knowledge of the future (usually said to be obtained from a
         divine source) [syn: prophecy, prognostication,
         vaticination]
    2: a prediction uttered under divine inspiration [syn:
       prophecy, divination]

The Devil's Dictionary (1881-1906):

PROPHECY, n.  The art and practice of selling one's credibility for
future delivery.