brain

noun
\ ˈbrān How to pronounce brain (audio) \

Definition of brain

 (Entry 1 of 2)

1a : 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
2a(1) : intellect, mind has a clever brain
(2) : intellectual endowment : intelligence often used in plural plenty of brains in that family
b(1) : a very intelligent or intellectual person
(2) : the chief planner within a group usually used in plural she's the brains behind their success
3 : something that performs the functions of a brain especially : an automatic device (such as a computer) for control or computation

brain

verb
brained; braining; brains

Definition of brain (Entry 2 of 2)

transitive verb

1 : to kill by smashing the skull
2 : to hit on the head

Illustration of brain

Illustration of brain

Noun

brain 1a: 1 cerebral hemisphere, 2 corpus callosum, 3 ventricle, 4 fornix, 5 thalamus, 6 pituitary gland, 7 pons, 8 medulla oblongata, 9 spinal cord, 10 cerebellum, 11 midbrain

In the meaning defined above

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Examples of brain in a Sentence

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.
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Recent Examples on the Web: Noun The horse, which also died, is believed to have suffered either a heart attack or brain aneurysm, Beauregard Parish Sheriff's Office's Chief Detective Sylvester Denmond told CBS affiliate KPLC. PEOPLE.com, 6 Oct. 2021 In Chicago, the drugs of choice for the city’s youth are Ecstasy and Xanax, two poles of brain-chemistry manipulation that serve to offset the pain of day-to-day life. Jeff Ihaza, Rolling Stone, 6 Oct. 2021 Beyond smartwatch wearables, exciting new advances are being made in adding sleep tracking technology to jewelry, textiles and even brain-tracking caps and earbuds. Chris Fernandez, Forbes, 6 Oct. 2021 The execution had been halted in the past because of claims that the drug used in the lethal injection would cause seizures for Johnson, who underwent brain surgery in 2008 to remove part of a tumor. al, 6 Oct. 2021 That’s when the visions would end, the brain editing out the unspeakable parts. New York Times, 5 Oct. 2021 But not every candidate has a thinking style that’s well-suited for brain teasers, Cole says. Mirel Zaman, refinery29.com, 5 Oct. 2021 There was one last series of tests to administer, in order to confirm brain function. Danielle Turchiano, Variety, 5 Oct. 2021 The mosquito-borne virus causes severe brain inflammation in about 2% of infected adults and 6% of infected children. CBS News, 5 Oct. 2021 Recent Examples on the Web: Verb Arguably, achieving universal health care and higher education and addressing the nation’s aging water pipe infrastructure (which has yielded a modern-day lead crisis) could be expected to make similar contributions to brain health across decades. Daniel R. George, Scientific American, 25 Aug. 2021 Then of course there’s me, spying on these other women — and some dads, too — instead of keeping tabs on my four kids, one of whom is poised to brain somebody with a stick. Washington Post, 4 June 2021 Biden, who lost his son Beau Biden to brain cancer in 2015, has pledged to make the fight against cancer a key focus of his administration. Dom Calicchio, Fox News, 25 Mar. 2021 The priority is personal to Biden, who lost his son Beau Biden to brain cancer in 2015. Marisa Schultz, Fox News, 20 Feb. 2021 This less average bone and muscle support makes the head and brain more vulnerable to sudden movement and predicts risk for concussion. Bob Roehr, Scientific American, 9 Mar. 2016 To Rio’s distress, a group of boys at a table nearby start to flirt coarsely with the overdeveloped and somewhat under-brained Pucha. Deborah Eisenberg, The New York Review of Books, 27 May 2020 The people who can make an outsized difference bring a combination of what is conventionally known as left-brained and right-brained thinking. Quartz India, 11 Feb. 2020 This has meant keeping the games going even as the league faced everything from domestic abuse cases to brain injuries. Jason Parham, WIRED, 15 Aug. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'brain.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of brain

Noun

before the 12th century, in the meaning defined at sense 1a

Verb

14th century, in the meaning defined at sense 1

History and Etymology for brain

Noun

Middle English, from Old English brægen; akin to Middle Low German bregen brain, and perhaps to Greek brechmos front part of the head

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Time Traveler for brain

Time Traveler

The first known use of brain was before the 12th century

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Dictionary Entries Near brain

braillewriter

brain

brain attack

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Statistics for brain

Last Updated

9 Oct 2021

Cite this Entry

“Brain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain. Accessed 18 Oct. 2021.

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More Definitions for brain

brain

noun

English Language Learners Definition of brain

 (Entry 1 of 2)

: the organ of the body in the head that controls functions, movements, sensations, and thoughts
: the ability to think and reason : intelligence
: a very intelligent person

brain

verb

English Language Learners Definition of brain (Entry 2 of 2)

: to hit (someone) on the head very hard

brain

noun
\ ˈbrān How to pronounce brain (audio) \

Kids Definition of brain

 (Entry 1 of 2)

1 : the part of the nervous system that is inside the skull, consists of grayish nerve cells and whitish nerve fibers, and is the organ of thought and the central control point for the nervous system
2 : the ability to think : intelligence
3 : someone who is very smart

brain

verb
brained; braining

Kids Definition of brain (Entry 2 of 2)

: to hit on the head very hard

brain

noun
\ ˈbrān How to pronounce brain (audio) \

Medical Definition of brain

1 : 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

More from Merriam-Webster on brain

Nglish: Translation of brain for Spanish Speakers

Britannica English: Translation of brain for Arabic Speakers

Britannica.com: Encyclopedia article about brain

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