Did you know?

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

crystal - 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     crystal pronunciation in American English
Word Forms
  1. 1
    [uncountable] clear glass of very good quality

    a set of crystal wine glasses

    1. a.
      objects such as glasses and bowls made from crystal

      We should use the good crystal at dinner tonight.

  2. 2
    [countable] chemistry a piece of a substance that has a regular shape with many sides and is formed when the substance becomes solid
  3. 3
    [countable/uncountable] a clear rock that looks like glass, especially quartz
    1. a.
      a piece of crystal used as a jewel

      a crystal necklace

  4. 4
    [countable] the piece of glass or plastic that protects the face of a clock or watch


to manipulate someone psychologically so that they begin to question their own perceptions and memories

BuzzWord Article

Open Dictionary

Dunning-Kruger effect

the phenomenon by which an incompetent person is too incompetent to understand his own incompetence

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