: the portion of the vertebrate central nervous system enclosed in the skull and continuous with the spinal cord through the foramen magnum that is composed of neurons and supporting and nutritive structures (such as glia) and that integrates sensory information from inside and outside the body in controlling autonomic function (such as heartbeat and respiration), in coordinating and directing correlated motor responses, and in the process of learning compare forebrain, hindbrain, midbrain
b
: a nervous center in invertebrates comparable in position and function to the vertebrate brain
Noun
Scientists are learning more about how the human brain works.
The left and right sides of the brain have different functions.
The other children always teased him about being such a brain. Verb
The tree limb fell and nearly brained me.
Recent Examples on the Web
Noun
Another theory on what causes brain fog in women could be linked to the body’s immune system response, which can cause inflammation in the brain.—Sandra Rose Salathe, Flow Space, 22 July 2024 Practice meditation Meditation pauses interaction with the outside world and offers the brain a chance to really rest and check-in.—Jeanne Ballion, Vogue, 22 July 2024
Verb
Space snake brains Joysticking EELS around on Enceladus was out of the question due to the huge communication lag, so the team went for nearly complete autonomy.—Jacek Krywko, Ars Technica, 3 Apr. 2024 The new set of donors, by contrast, come from the first category and are not brain dead.—Joseph Goldstein, New York Times, 22 Nov. 2023 See all Example Sentences for brain
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'brain.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
Etymology
Noun
Middle English, from Old English brægen; akin to Middle Low German bregen brain, and perhaps to Greek brechmos front part of the head
First Known Use
Noun
before the 12th century, in the meaning defined at sense 1a
: the portion of the central nervous system of vertebrate animals that is the organ of thought and the central control point for the nervous system, is enclosed within the skull, and is continuous with the spinal cord
b
: the main nervous center in an invertebrate animal
: the portion of the vertebrate central nervous system enclosed in the skull and continuous with the spinal cord through the foramen magnum that is composed of neurons and supporting and nutritive structures (as glia) and that integrates sensory information from inside and outside the body in controlling autonomic function (as heartbeat and respiration), in coordinating and directing correlated motor responses, and in the process of learning see forebrain, hindbrain, midbrain
2
: a nervous center in invertebrates comparable in position and function to the vertebrate brain
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