What is the meaning of Mystery?

Something secret or unexplainable; an unknown.

Someone or something with an obscure or puzzling nature.

An account, story, book, film, or play, often with the theme of crime or murder, with a surprise ending that explains all the strange events that have occurred.

A secret or mystical meaning.

A religious truth not understandable by the application of human reason alone (without divine aid).

A sacrament.

A secret religious celebration, admission to which was usually through initiation.

A particular event or series of events in the life of Christ.

A craft, art or trade; specifically a guild of craftsmen.

Alternative form of mysterie (mystery)

Alternative form of mysterie (duty)

Source: wiktionary.org