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 False-memory researchers remain skeptical of the brain-imaging studies. Joshua Kendall, Scientific American, "Forgotten Memories of Traumatic Events Get Some Backing from Brain-Imaging Studies," 6 Apr. 2021 Jarreau's close childhood friend from New Orleans, Tristen Edgerson, died this week after suffering a brain aneurysm. Scott Gleeson, USA TODAY, "Houston's DeJon Jarreau playing in Final Four with a guardian angel — his late childhood friend," 3 Apr. 2021 Clicking the mouse button reverts the direction of the ball, turning the simple act of movement into a brain-contorting, puzzle-solving exercise. Vincent Acovino, Wired, "Qomp Makes a Case for Shorter, Simpler Video Games," 2 Apr. 2021 Spoken words snippets, brain-popping textures, emotional melodies and hiccuping rhythms swirl together in an exciting mash-up of styles and tastes. Katie Bain, Billboard, "First Spin: The Week's Best New Dance Tracks From Wavedash, Sofi Tukker, Deadmau5 & More," 2 Apr. 2021 In a December 2020 study, researchers identified five new viruses in the bears showing the symptoms, but whether any of these viruses cause the brain-swelling illness and odd behaviors remains unclear, Gizmodo reports. Elizabeth Gamillo, Smithsonian Magazine, "A Puzzling Brain Disease Is Killing Black Bears in the Western United States," 30 Mar. 2021 Hortencia Ramos recalled how eight years ago, her cousin Javier suffered a brain aneurysm and almost died. Daniel I. Dorfman, chicagotribune.com, "Vigil honors life of Franklin Park ride share driver shot and killed in Chicago carjacking," 27 Mar. 2021 Up to bat came Matt Dobson, a senior who lost his mother, Mary, to a brain aneurysm two weeks ago. Eric Sondheimer Columnist, Los Angeles Times, "Prep baseball roundup: Matt Dobson, playing for his mother, hits walk-off home run," 20 Mar. 2021 Ochoa, who suffers from diabetes and recovered from a brain aneurysm before the pandemic, was vaccinated earlier this year. Nicole Chavez, CNN, "A grandmother was eager to get a Covid-19 vaccine. She called a hotline but no one answered for weeks," 11 Mar. 2021 Recent Examples on the Web: Verb 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, "Biden’s claim that 'dogs may help cure cancer' draws Twitter reactions," 25 Mar. 2021 The priority is personal to Biden, who lost his son Beau Biden to brain cancer in 2015. Marisa Schultz, Fox News, "Biden says once he defeats COVID, cancer is next," 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, "Concussions Affect Women More Adversely Than Men," 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, "Tyrannical Days," 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, "Kunal Shah on the jobs that will define India’s future," 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, "Depth of Field: Where Is Jay-Z Taking the NFL?," 15 Aug. 2019 The yawning space between is echoed by an endless lateral runway that makes every entrance and exit seem like a trek and requires the actors to duck their heads to avoid getting brained on the way out. David Rooney, The Hollywood Reporter, "'The Rose Tattoo': Theater Review," 16 Oct. 2019 Yet focusing on chicken shops is not completely bird-brained. The Economist, "A British anti-knife drive comes home to roost," 22 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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Statistics for brain

Last Updated

12 Apr 2021

Cite this Entry

“Brain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/brain. Accessed 17 Apr. 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
informal : the ability to think and reason
informal : a very intelligent person

brain

verb

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

informal : 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

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Comments on brain

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