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brain

n. · v.
US //ˈbɹeɪn// UK //bɹˈeɪn// brain
  1. 1 the organ (n.)
    A2 Elementary

    the organ inside your head that controls your body, thoughts, and feelings.

    the primary organ of the central nervous system in the skull, responsible for cognition, memory, and motor control.

    Example

    The human brain uses a lot of energy even when you are sleeping.

    Example

    Neuroscientists are still mapping the complex neural pathways within the human brain to understand how memory is stored.
  2. 2 intelligence (n.)
    B1 Intermediate

    your ability to think, learn, and solve problems.

    intellectual capacity or mental ability; often used in the plural to refer to high intelligence.

    Example

    She has the brains to become a doctor if she works hard.

    Example

    It took a lot of brains to figure out the logistics of moving the entire office over a single weekend.

    Usage

    Often used in the plural form 'brains' when referring to general intelligence.
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  1. 3 a smart person (n.)
    B2 Upper Intermediate Informal

    a person who is very intelligent.

    a highly intelligent person, often one who provides the intellectual leadership for a project.

    Example

    Ask Sarah for help with the math homework; she is the brain of the class.

    Example

    He was known as the brain behind the operation, coordinating every technical detail from the home office.
  2. 4 computer control center (n.)
    B2 Upper Intermediate Computing

    the part of a machine or computer that does the thinking and calculations.

    the central processing unit or control mechanism of a machine, likened to a biological brain.

    Example

    The computer's brain was damaged when the coffee spilled on the desk.

    Example

    The onboard computer serves as the brain of the spacecraft, managing life support and navigation systems simultaneously.
  3. 5 to hit on the head (v.)
    C2 Proficiency Informal

    to hit someone very hard on the head.

    to strike someone forcefully on the head; historically, to kill by smashing the skull.

    Example

    The cartoon character tried to brain the giant with a large wooden hammer.

    Example

    In the old adventure novel, the hero nearly got brained by a falling rock while escaping the cave.

    Usage

    This verb is transitive and requires a direct object.

    Teacher's tip

    This is quite violent and informal; it is often used in a slightly exaggerated or humorous way in modern speech.
Origin

From Middle English brayn, brain, from Old English bræġn (“brain”), from Proto-West Germanic bragn, from Proto-Germanic bragną (“brain”), from Proto-Indo-European mregʰnom (“skull, brain”), from Proto-Indo-European mregʰ- (“marrow, sinciput”) + *-mn̥ (“nominal suffix”). Cognate with Scots braine, brane (“brain”), North Frisian brayen, brein, Brain (“brain”), Saterland Frisian Brainge, Bräienge (“brain”), West Frisian brein (“brain”), Dutch brein (“brain”), Low German Brägen, Bregen (“brain”) (whence German Bregen (“animal brain”)), Ancient Greek βρεχμός (brekhmós, “front part of the skull, top of the head”).

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