mystery

from The Century Dictionary.

• noun Occupation; trade; office; profession; calling; art; craft.
• noun plural In ancient religions, rites known to and practised by certain initiated persons only, consisting of purifications, sacrificial offerings, processions, songs, dances, dramatic performances, and the like: as, the Eleusinian mysteries.
• noun In the Christian Church, especially in the early church and in the Greek Church, a sacrament.
• noun plural The consecrated elements in the eucharist; in the singular, the eucharist.
• noun Any religious doctrine or body of doctrines that seems above human comprehension.
• noun They counte as Fables the holie misteries of Christian Religion.
• noun In general, a fact, matter, or phenomenon of which the meaning, explanation, or cause is not known, and which awakens curiosity or inspires awe; something that is inexplicable; an enigmatic secret.
• noun A form of dramatic composition much in vogue in the middle ages, and still played in some parts of Europe in a modified form, the characters and events of which were drawn from sacred history.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun A kind of secret religious celebration, to which none were admitted except those who had been initiated by certain preparatory ceremonies; -- usually plural.
• noun The consecrated elements in the eucharist.
• noun Anything artfully made difficult; an enigma.
• noun A trade; a handicraft; hence, any business with which one is usually occupied.
• noun A dramatic representation of a Scriptural subject, often some event in the life of Christ; a dramatic composition of this character.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Something secret or unexplainable; unknown.
• noun Someone or thing with an obscure or puzzling nature.
• noun Catholicism A particular event or series of events in the life of Christ.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun something that baffles understanding and cannot be explained
• noun a story about a crime (usually murder) presented as a novel or play or movie