mystery

plural mysteries

1. countableuncountableSomething secret or unexplainable; an unknown.

   The truth behind the events remains a mystery.

   2 more examples

   The case was that of a murder. It had an element of mystery about it, however, which was puzzling the authorities. A turban and loincloth soaked in blood had been found; also a staff.

   1927, F. E. Penny, chapter 4, in Pulling the Strings

   The fate of the railway from Ballater to Braemar has been invested with an air of mystery, which has never been completely dispelled. It has been suggested that Queen Victoria was opposed to a railway in the vicinity of Balmoral Castle, and intervened personally to secure the abandonment of the line beyond Ballater.

   1957 January 28, H. A. Vallance, “The Deeside Railway—1”, in Railway Magazine, page 6

2. countableuncountableSomeone or something with an obscure or puzzling nature.

   That man is a mystery.

   1 more example

   Then I had a good think on the subject of the hocussing of Cigarette, and I was reluctantly bound to admit that once again the man in the corner had found the only possible solution to the mystery.

   1904–1905, Baroness Orczy [i.e., Emma Orczy], “The Hocussing of Cigarette”, in The Case of Miss Elliott, London: T[homas] Fisher Unwin, published 1905, →OCLC; republished as popular edition, London: Greening & Co., 1909, OCLC 11192831, quoted in The Case of Miss Elliott (ebook no. 2000141h.html), Australia: Project Gutenberg of Australia, February 2020

3. countableuncountableAn 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.
4. countableuncountableA mystery play.

   The Moralities displayed something more of art and invention than the Mysteries; in them virtues, vices and qualities were personified, and something like a plot was frequently to be discovered.

   1862, George Borrow, Wild Wales

5. countableobsoleteuncountableA secret or mystical meaning.

   […] and, not knowing the meaning or misterie of her pollicie, forgat no termes of reproche or rigorous rebuke against his chast doughter.

   1567, Matteo Bandello, Certain Tragical Discourses of Bandello, tr. Geffraie Fenton

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

   1744 (first printed), Jonathan Swift, A Sermon on the Trinity 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.

7. countableuncountablearchaic outside Eastern OrthodoxyA sacrament.

   There are seven mysteries, or sacraments, in the Greek church, viz. baptism, the chrism (a rite peculiar to this church), the eucharist, confession, ordination, marriage, and the holy oil.

   1809, Sir Robert Ker Porter, Travelling Sketches in Russia and Sweden: During the Years 1805, 1806, 1807, 1808

8. countablein pluraluncountableA secret religious celebration, admission to which was usually through initiation.

   the Eleusinian mysteries

   3 more examples

   the Mysteries of Mithras

   There’s no initiation either into such mysteries.

   1899 February, Joseph Conrad, “The Heart of Darkness”, in Blackwood’s Edinburgh Magazine, volume CLXV, number M, New York, N.Y.: The Leonard Scott Publishing Company, […], →OCLC, part I, page 196

   It is, indeed, part of the ritual of the candidate for adeptship into the British mysteries, resembling that for the neophyte into the Osirian, Cabiric or Orphean mysteries.

   1928, Lewis Spence, Mysteries of Britain, page v. 123

9. countableuncountableCatholicismA particular event or series of events in the life of Christ.

   The second decade of the Rosary concerns the Sorrowful mysteries, such as the crucifixion and the crowning with thorns.

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

    The trades, the crafts, the mysteries, would all be losers.

    1776, Adam Smith, An Inquiry into the Nature and Causes of the Wealth of Nations