Source : Webster's Revised Unabridged Dictionary (1913)

Mystery \Mys"ter*y\, n.; pl. {Mysteries}. [OE. mistere, OF.
   mestier, F. m['e]tier, L. ministerium. See {Ministry}.]
   1. A trade; a handicraft; hence, any business with which one
      is usually occupied.

            Fie upon him, he will discredit our mystery. --Shak.

            And that which is the noblest mystery Brings to
            reproach and common infamy.           --Spenser.

   2. A dramatic representation of a Scriptural subject, often
      some event in the life of Christ; a dramatic composition
      of this character; as, the Chester Mysteries, consisting
      of dramas acted by various craft associations in that city
      in the early part of the 14th century.

            ``Mystery plays,'' so called because acted by
            craftsmen.                            --Skeat.

Mystery \Mys"ter*y\, n.; pl. {Mysteries}. [L. mysterium, Gr. ?,
   fr. ? one initiated in mysteries; cf. ? to initiate into the
   mysteries, fr. ? to shut the eyes. Cf. {Mute}, a.]
   1. A profound secret; something wholly unknown, or something
      kept cautiously concealed, and therefore exciting
      curiosity or wonder; something which has not been or can
      not be explained; hence, specifically, that which is
      beyond human comprehension.

            We speak the wisdom of God in a mystery. --1 Cor.
                                                  ii. 7.

            If God should please to reveal unto us this great
            mystery of the Trinity, or some other mysteries in
            our holy religion, we should not be able to
            understand them, unless he would bestow on us some
            new faculties of the mind.            --Swift.

   2. A kind of secret religious celebration, to which none were
      admitted except those who had been initiated by certain
      preparatory ceremonies; -- usually plural; as, the
      Eleusinian mysteries.

   3. pl. The consecrated elements in the eucharist.

   4. Anything artfully made difficult; an enigma.

Source : WordNet®

mystery
     n 1: something that baffles understanding and cannot be
          explained; "how it got out is a mystery"; "it remains
          one of nature's secrets" [syn: {enigma}, {secret}, {closed
          book}]
     2: a story about a crime (usually murder) presented as a novel
        or play or movie [syn: {mystery story}, {whodunit}]