Did you know?

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


 - definitions and thesaurus

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.



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 principle pronunciation in American English /ˈprɪnsəp(ə)l/
Word Forms
  1. 1
    [countable] a basic belief, theory, or rule that has a major influence on the way in which something is done

    Excellent customer service should be our guiding principle.

    principle of:

    It is a basic principle of English law that a person is innocent until proven guilty.

    principle that:

    the principle that education should be free to everyone

    1. a.
      [often plural] one of the major ideas or theories that a system of beliefs is based on, for example in religion or politics

      Marxist/Buddhist/democratic principles

      the principles and ideals that the party stands for

  2. 2
    [countable] [usually plural] a basic rule or belief about what is right and morally good, that influences the way that you behave and the way that you treat other people

    He seems to have absolutely no principles.

    against someone’s principles:

    It was against their principles to join the military.

    stick to/stand by your principles:

    Bennett stuck to his principles, and refused to name the source of his information.

    1. a.
      [uncountable] morally correct behavior

      a woman of principle

      on principle:

      We are opposed on principle to any collaboration with terrorists.

      a point/matter/issue of principle:

      There are some basic issues of principle relating to the debate about abortion.

  3. 3
    [countable] a scientific theory or basic natural law that explains the way in which something works

    Windmills differ in design, but all operate on exactly the same principle.

    Heisenberg’s Uncertainty Principle

    principle of:

    It was Darwin who first identified the “principle of female choice.”



… a teaching method in which groups of children learn independently using a computer linked to the internet

BuzzWord Article

Open Dictionary


a derogatory word used for referring to people in the banking and investment industry who are thought of as taking serious risks in order to increase their own earnings …

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