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brain

BRAYN/bɹeɪn/

Pluralbrains

13 meanings of brain

Practice

  1. 1
    body organnouncountable or uncountable
    The organ inside your head that controls thinking, feeling, and moving.

    Like the control room of a building, sending orders to everything else.

    The brain sends signals to every part of the body.

    A hard blow to the head can damage the brain.

  2. 2
    mindnouncolloquialcountable or uncountable
    A person's mind, where thoughts and ideas happen.

    Like a room in your head where thoughts come and go.

    I can't get that song out of my brain.

    Her brain was full of worries before the trip.

    UsageOften stuck in my brain.

    Similarmind, head

    Note
  3. 3
    thinking powernouncountable or uncountableplural
    The ability to think, learn, and understand things, in general or for a certain job.

    Like a muscle you train to get better at thinking.

    You'll need to use your brain to solve this puzzle.

    She has the brains to solve really hard math problems.

    Similarintelligence, intellect, mind, wit

  4. 4
    part of organnouncountable or uncountable
    A part of the brain that handles a certain kind of thinking or feeling.

    Like one department in a big office, each doing its own job.

    The reptilian brain controls our most basic survival instincts.

    Fear starts deep inside the emotional brain.

    UsageUsually with a word before it: the left brain.

    Note
  5. 5
    chief plannernouncolloquialcountable or uncountableplural
    The person who does the thinking or planning for a group.

    Like the player who plans the strategy while the others carry it out.

    She was the brain behind the surprise party.

    Tom is the brains of the band and writes every song.

    UsageOften the brains behind a plan.

    Similargenius, thinker, mind

Practice

Can you tell the meanings of brain apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.

Origin

It comes from Old English bræġn, meaning 'brain', probably going back to an ancient root for 'skull' or 'brain'.

Checked 31 Oct 2026 · 2 facts