Definition of brain in US English:



  • 1An organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating center of sensation and intellectual and nervous activity.

    The human brain consists of three main parts. (i) The forebrain, greatly developed into the cerebrum, consists of two hemispheres joined by a bridge of nerve fibers, and is responsible for thought and control of speech. (ii) The midbrain, the upper part of the tapering brainstem, contains cells involved in eye movements. (iii) The hindbrain, the lower part of the brainstem, contains cells responsible for breathing and for regulating heart action, the flow of digestive juices, and other unconscious actions and processes. The cerebellum, which lies behind the brain stem, plays an important role in the execution of highly skilled movements

    • ‘Surgeons must now carry out a strict assessment before patients undergo surgical procedures on tissues such as the brain, spinal cord, eye, spleen and tonsils.’
    • ‘This can change the activity of certain nerve cells and influence brain activity.’
    • ‘The movements your muscles make are coordinated and controlled by the brain and nervous system.’
    • ‘Nervous tissues such as the brain, spinal cord and ganglia seemed to be the main sites of viral replication.’
    • ‘Each individual radiation beam is too weak to harm the brain tissue it passes through.’
    • ‘In multiple sclerosis, the immune system attacks the brain and nervous system.’
    • ‘More possibilities lie ahead for heart patches and repair of the dura mater tissue that protects the brain and spinal cord.’
    • ‘Fish are vertebrates, with a brain, a central nervous system and pain receptors all over their bodies, including the lips.’
    • ‘Once in a child's bloodstream the lead travels to the brain, soft tissue and bones.’
    • ‘It is a precious tissue like the nervous tissue of the brain, spinal cord and heart muscle, as it cannot heal like the other tissues.’
    • ‘Moreover, while dressing game, hunters expose themselves to the most infectious tissues, the brain and spinal cord.’
    • ‘Stem cells are harvested from bone marrow, umbilical cords, the brain and spinal cord and other tissues.’
    • ‘This edema affects many organs, including the brain, kidneys, liver, and lungs.’
    • ‘The tumor was located in the pineal gland and was well demarcated from the surrounding brain tissue, especially from the cerebellum.’
    • ‘This occurs as a result of damage to soft brain tissue when the brain rattles against the skull.’
    • ‘They also learned various ways to identify the diseased brain tissue that causes seizures.’
    • ‘Primary brain tumours may arise from several different kinds of tissue.’
    • ‘When this occurs, the swollen brain tissue will push the other contents of the skull to the side.’
    • ‘This may result in a blockage of the cerebrospinal fluid, the fluid that bathes the brain and spinal cord.’
    • ‘Scientists have identified a gene variation that sparks heightened activity in our brain's fear centre.’
    cerebrum, cerebral matter
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    1. 1.1brains The substance of an animal's brain used as food.
      • ‘But brains from younger animals will still be considered fit for human consumption.’
      • ‘I'd say ‘sure’ and Billy would come in shortly afterwards and order the calf's brains.’
      • ‘Feeding herbivores scientifically patented diets of ground sheep and beef meat, brains, and minced bone meal, is absolutely insane.’
      • ‘One verb applies to mushy, gelatinous, overripe, and overcooked things, of which brains, bananas, and avocados might be examples.’
      • ‘Well, some people eat dogs and monkey brains and you might think that's disgusting… so stop trying to convince me to try black licorice.’
      • ‘Crispy sauteed brains sold like hotcakes as a first course at Bistro Felix in SoHo.’
      • ‘Imagine the explaining I had to do when I brought David Milne home from school, only to find two sheep's brains on the table - remnants of my dad's lunch.’
      • ‘It was also at the River Cafe, after graduating in liver appreciation, that I went on to discover the pleasures of sweetbreads, kidneys, tongues and brains.’
      • ‘When he and mum looked at them they found many of her old staples - not pig brains, admittedly - there in the ‘healthy’ columns.’
      • ‘The ravioli lies flaccidly at the top of the plate; beneath it, in a mockingly straight line, are the four rabbit brains… Flopsy, Mopsy, Cottontail and Peter.’
      • ‘Battali has been dishing brains, tripe, and ravioli stuffed with veal cheek for a couple of years.’
      • ‘The Bochka serves pigs roasted on a spit, veal brains with mushrooms in a pot, and grilled salmon.’
      • ‘There was a mixed dish of kidneys, brains and something else on the menu, so we asked the waiter what it was.’
      • ‘It traditionally contains sweetbreads, brains, porcini mushrooms and chicken livers.’
      • ‘Thankfully, they were the brains of little lambs or baby calves, rather than the full Lecter smorgasbord, but even so, it was revolting to find as you rooted around for the milk first thing in the morning.’
      • ‘Lightly flour the calves' brains and sauté until light brown.’
      • ‘These conditions are not always met - otherwise good brains are often discoloured by blood clots.’
      • ‘This anticipates a love of chitterlings, grilled pig's ears, marrow bones, stuffed trotters, kidneys and brains.’
      • ‘The cutlet-size veal cheeks and tongue and a fist of brains were simmered in stock with vegetables.’
      • ‘What Rosa sells is sheep's heads, brains, intestines, stomach linings, pig's feet, and big, white, oval, veined bulls' testicles.’
    2. 1.2informal An electronic device with functions comparable to those of the human brain.
      • ‘The only remnants of the human race are in the microchip brain of a robot.’
      • ‘Soon electronic brains would replace most of the accounting department, the typing pool, and the switchboard.’
      • ‘The Brain - The brain of a search engine, like the human brain, is the most complex of its functions and components.’
      • ‘The accompaniment to his poetry came directly from the electronic brain of his keyboard.’
      • ‘TI is the No. 1 seller of chips for cell phones, supplying the brains of the snazziest multimedia models in the market.’
      • ‘That shutter speed that the electronic brain says is incorrect, might just give you a wonderful emotive blurry shot that is an award winner!’
      • ‘An advanced robotics technology is developed in the early 2050's, allowing for robotic brains with the capacity to learn.’
      • ‘Another area where the electronic brain is clueless is when you want to take tricky shots using the flash.’
      • ‘A 2005 model of a Brilliant Pebble would be smaller and have a better electronic brain than the 1993 one.’
      • ‘All it takes to turn these pieces into a robot is packaging the brains and the senses atop a mobile platform and stirring in some clever code.’
      • ‘For once, Harry Flashman is happy to let the electronic brain do its thing (but without the flash).’
      • ‘If a light shines on it, the brain sends out an electronic pulse.’
      • ‘It was not a straight line course either; the unmanned vehicles had to use their computer brains and sensing devices to follow a programmed route and avoid hitting obstacles.’
  • 2Intellectual capacity.

    ‘I didn't have enough brains for the sciences’
    ‘success requires brain as well as brawn’
    • ‘That's because actually, feminists think men should be treated as fully functional human beings with brains and morals who should be held responsible for the choices they make.’
    • ‘If the person were really dynamic and had the brains, they could even swing themselves into a management position at some point.’
    • ‘I mean, lord have mercy, I wouldn't even begin to tax my brain trying to think I had to stay in style.’
    • ‘Vultures don't have the brains to know how to cut a rope.’
    • ‘I think we are also given enough-it goes with the whole thing of what God has given us as far as our brains and our mental capacity goes.’
    • ‘Thankfully, the mother had brains enough to send her away again.’
    • ‘Take your damn ideas, training, brains, and intelligence, all the things we're paying you for, and shove it.’
    • ‘Happiness is not enough; brains are not enough; goodness will get you by, but without the other two it's a shield made of straw.’
    • ‘It is an interesting game that won't exactly tax the brain but feeds the public even more of the voyeuristic TV is so obviously craves!’
    • ‘It believe it is nonsensical and that God gave us the brains to know right from wrong.’
    • ‘Not only has the 19 year old UCD student got the looks, the brains, and the personality but she's also got one of the world's top selling singers as a father.’
    • ‘I don't want to tax my brain too much.’
    • ‘Even if he didn't he would have learnt his lesson, assuming he had the brains to understand what it all meant.’
    • ‘They have the brains to match their beauty and are out to prove that they are more than just pretty faces when they are joined by 32 others vying for the title in Bournemouth.’
    • ‘You have the brains of the average eight-year-old.’
    • ‘How often had I heard talk of superstitious idiots, often relatives, who worshipped a God they didn't have the brains to doubt?’
    • ‘With beauty, brains and talent, Padma Lakshmi - aka Mrs Salman Rushdie - hardly needs to find the way to a man's heart through his stomach.’
    • ‘She has the brains to be at any school, anywhere.’
    • ‘After all, it's not likely to be particularly taxing on the brain and I quite like the idea of getting paid when I'm not at my most alert.’
    • ‘I'm Dave Winer without the brains and the money.’
    intelligence, intellect, intellectual capacity, mental capacity, brainpower, cleverness, wit, wits, powers of reasoning, reasoning, wisdom, sagacity, acumen, discernment, shrewdness, judgement, understanding, common sense, sense
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    1. 2.1the brainsinformal A clever person who supplies the ideas and plans for a group of people.
      ‘Tom was the brains of the outfit’
      • ‘Could this be the big mo for Ben, Mena and Anil, the brains and the energy behind Typepad and Movable Type?’
      • ‘Catherine Ring was the brains behind The Newspaper Headlines from the past.’
      • ‘It wasn't like he was the brains of the operation, but he was a figure to be reckoned with.’
      • ‘As Toti remarks with a pinch of irony: ‘Nell's the brains, I'm the brawn.’’
      • ‘It's time to ask Tommy Champion, the brains and energy behind this event some questions.’
      • ‘‘Genie’ Dukkha was the leader; the brains of an outfit which admittedly could hardly be mistaken for Mensa.’
      • ‘Gale was the brains of the group - the only one with at least half a brain and the mind to use it.’
      • ‘I suspected that she was the brains of the outfit.’
      • ‘Paldawar was the brains of this outfit, not Dain.’
      • ‘The progressives have the brains and the moral highroad.’
      • ‘While Pita may have the brains, lets hope he has a good team that guides him in the political gamesmanship he will face.’
      • ‘Morgan, an apparently irascible old codger, is quite literally the brains of the outfit.’
      • ‘It seems that Campbell may have been the brawn and the brains of their outfit.’
      • ‘Ansett liberated them from the old firm and set them up in KordaMentha (putting the brains of the outfit up front there).’
      • ‘Westwood and McLaren were viewed differently - he as the brains and she the workhorse.’
      clever person, intellectual, intellect, bluestocking, thinker, highbrow, mind, scholar, sage
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    2. 2.2 A person's mind.
      ‘a tiny alarm bell began to ring in her brain’
      • ‘This show programmed a seasonal habit into the brains of my siblings and myself.’
      • ‘But soon enough your brain starts to run out of gas - opinions, ideas, plans start to float away.’
      • ‘John / Halcyon stuck a mental tag in the folds of my brain: optimism tax.’
      • ‘It's enough to rot the brain were it not for its sheer entertainment value.’
      • ‘I'll do the wracking of the brains to think of something new to write each time.’
      • ‘Every once in a while, my brain would clear enough to do some mindless chore, like fill the water pots or fold the blankets, but otherwise, I felt numb.’
      • ‘Some part of my brain was sane enough to understand that the others would arrive with a straightjacket if they heard me talk to empty space.’
      • ‘A painful piece of memory flashed through her brain and gave her extra strength.’
      • ‘If your brain is working well enough for you to get a good, uh, score on this quiz, it means the stuff isn't working.’
      • ‘That connection happens in two places: on the board, and in the brains of the participants.’
      • ‘It'll be interesting to see where fresh brains take this idea.’
      • ‘I buy expensive creams to put on my skin, even though my science brain knows they don't achieve much.’
      • ‘Wouldn't that exercise the brains of our kids more?’
      • ‘We are usually such a perceptive people, I suppose histrionics really numbs the brains and being superheroes is something no one can resist.’
      • ‘Sometimes though, the tracks are actually too boring and don't do nearly enough to get the brain working.’
      • ‘If you don't have time to read the whole thing, the summary at the beginning should be enough to get your brain working a little bit.’
      • ‘I simply couldn't grasp this idea with my mind, especially with my brain rattled up enough as it was.’
      • ‘It could be the tests weren't hard enough for the female brain, he said.’
      • ‘The memories flooded into his brain as though they had always been there.’
      • ‘Oddly though, once my brain internalized my surroundings as a surreal stage setting, removed from what would be normally acceptable to my senses, I felt at ease.’
      aptitude, knack, flair, bent, talent, gift, skill, art, trick, faculty, ability, propensity, inclination
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    3. 2.3 An exceptionally intelligent person.
      ‘he was known more as a snappy dresser than a brain’
      • ‘With the group of brains working at your clever paper, I just can't believe it.’
      • ‘Everyone knows who my brother is because he's a real brain.’
      • ‘Sure, when I was younger, there was always a certain amount of contempt for the "brains" in the class.’


[with object]informal
  • Hit (someone) hard on the head with an object.

    ‘she brained me with a rolling pin’
    • ‘I really thought he was going to brain me with his mighty fist.’
    • ‘You don't brain the guy so you can steal the pipe.’
    • ‘Somehow or another all concerned manage to avoid braining each other with guitars, mic stands and various other musical impedimenta.’
    • ‘And in the morning when I looked at him, I asked what he was in for, it seemed that he'd brained his superior officer with a rifle butt.’
    • ‘You could brain someone with this book: practically a cube, and over 1,000 pages, it could really do some damage.’
    • ‘My old man had nearly brained himself trying to install the heavy rope on the limb of an old box elder.’
    • ‘Thanks also to the projectionist for switching off his radio before someone got up to brain him.’
    • ‘Chairs had long ago been removed when one of the (now former) owners had been brained with one in the middle of one of Hvit's constant brawls.’
    • ‘I swear, if she didn't give it up soon I was going to brain her with the nearest object to hand.’
    • ‘My mother had once made me take ballet lessons until I'd brained the teacher with one of my slippers.’
    • ‘Say the child found the kitchen and brained him/herself with a toaster by pulling on the cord.’
    • ‘He then jumped into the crater with a knobkerrie and had brained another of the enemy when he was himself struck through the shoulder by a bayonet.’
    • ‘Girls that like braining other girls with lacrosse sticks?’
    • ‘You just had a mother, who home schooled her kids, sent to the loonie bin after she brained two of them.’
    • ‘That's when I stopped what I was doing, got out of bed and brained the one in the red pyjamas with my alarm clock.’
    • ‘In the Old Testament, two teenagers can't live together without one braining the other.’
    • ‘When you're single it's almost preferable to be unhappy in a crowd - at home, ‘human contact’ consists of bumping into the bookcase and getting brained by a falling volume of Tolstoi.’
    • ‘A metal bucket fell from the sky, braining the nearest bug.’
    • ‘In these streets he met Anitus, the king of the country, and brained him with his club, which was the fashion among gentlemen in those days.’
    • ‘As he burst in the door, Mrs. Luthor nearly brained him with the poker from the fireplace.’
    hit over the head, hit on the head, hit, strike, buffet, bang, knock, thwack, slug, welt, cuff, punch, smash
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  • have (got) something on the brain

    • informal Be obsessed with something.

      ‘John has cars on the brain’
      • ‘I have a patient on the brain as well.’
      • ‘He had my children on the brain and made me feel like I was a total failure.’
      • ‘‘I have titrations on the brain,’ I gasped, nosily sucking in air.’
      • ‘For most of my adult life I have had a tune on the brain.’
      • ‘The Core Team, as you probably know, has babies on the brain.’
      • ‘Peers and MPs had trains on the brain this week: the beloved Flying Scotsman, its clapped-out modern day equivalents which are, apparently, too small for fat people and those with broken-down loos.’
      • ‘Again I thought of Andreios, just a brief second, but the hair and appearance was again off (I really had guys on the brain, needed to get over this).’
      • ‘Or at least acknowledge that they have it on the brain as much as men do.’
      • ‘I have taken to shuffling about on the carpet with my rubber-soled shoes, distributing electric shocks because unlike the boys I don't have balls on the brain and rolling mouse balls along the carpet at a pin just doesn't interest me.’
      • ‘I've had interviews on the brain for the past few months - verbal ones, written ones, for business and for pleasure.’
      be fixated, be preoccupied, be infatuated, be possessed, be haunted, be consumed, be plagued, be tormented, be bedevilled, be eaten up, be gripped, be in the grip of, be dominated, be beset
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  • beat (or blow) someone's brains out

    • informal Injure or kill someone with a hard hit on (or gunshot to) the head.

      • ‘It's the day Isaac came to me and practically beat my brains out, and can you believe that even a year after it happened the wounds still sting and hurt.’
      • ‘While there was clear bitterness on his part toward the successor who had rushed ‘to undo everything I'd done,’ and the Republicans who ‘will run over you unless you beat their brains out,’ there was a feisty humor too.’
      • ‘From his Durley relations, he later learnt that the soldier had said that they had been about to beat his brains out with their musket-butts.’
      • ‘He insists he'd rather have someone beat his brains out with a crowbar than go back.’
      • ‘Shot in the Czech Republic for just $4 million, Hostel is filled with bombed-out warehouses, dank alleys and gangs of feral street kids ready to beat your brains out for bubblegum.’
      • ‘And so, he continued, ‘We need to go into the heart of their world and beat their brains out, in order to burst this bubble.’’
      • ‘Nail him in an alley some day and beat his brains out?’
      • ‘I made the mistake of hunkering down behind the sandbags, when I should have stepped up and beat his brains out.’
      • ‘I'd go stand in the outfield, and I didn't get too friendly or comfortable out there, because I knew I'd be facing these guys two days later and they'd be trying to beat my brains out.’
      • ‘If I catch anyone saying ‘Ah, God love him’ about me I shall tie them to the Blarney Stone and beat their brains out with a shillelagh.’


Old English brægen, of West Germanic origin; related to Dutch brein.