Did you know?

Click any word in a definition or example to find the entry for that word

mystery - definition and synonyms

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.

Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

noun     mystery pronunciation in British English
Word Forms
  1. 1
    [countable] something that you are not able to understand, explain, or get information about

    I just can’t think who she could have been – it’s a mystery.

    The exact origin of the universe remains a mystery.

    solve/unravel a mystery (=explain it):

    The police are trying to unravel the mystery of his disappearance.

    be a mystery to someone:

    Why she left is still a mystery to him.

  2. 2
    [uncountable] a quality that makes someone or something difficult to explain, understand, or get information about, especially when it also makes them seem interesting or exciting
    air/aura of mystery:

    a woman with an air of mystery about her

    shrouded/cloaked in mystery:

    His past is shrouded in mystery.

    1. a.
      [countable] someone or something that is interesting or exciting because they are difficult to explain, understand, or get information about

      David’s always been a bit of a mystery.

  3. 3
    [countable] a story, film, or play in which events take place that are not explained until the end, especially a crime such as murder

    an Ellery Queen mystery

  4. 4


    [plural] often humorous information about a subject or activity that only some people are allowed to know
    mystery of:

    You’ll learn all about the mysteries of the darkroom and printing processes.

  5. 5
    [countable] something relating to religion or God that you cannot explain using reason or science but that you believe is true

    the mystery of salvation

    1. a.
      in some branches of Christianity, another name for the sacraments (=holy ceremonies)

      belief in the Eucharistic mystery

    2. b.


      in many religions, secret rituals in which only certain people are allowed to take part

      The initiates in the Eleusinian mysteries hoped for a rebirth of Dionysus.

  • Facebook
  • Twitter


a lifestyle focussing on simple pleasures such as comfort and cosiness in the home, and spending time with friends and family

BuzzWord Article

Open Dictionary


a form of location that involves the underwater detonation of a bomb which causes sound waves that are picked up by ships

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play