brain

¹brain

noun \ˈbrān\

Definition of BRAIN

1

a : 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 — compare forebrain, hindbrain, midbrain

b : a nervous center in invertebrates comparable in position and function to the vertebrate brain

2

a (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 (as a computer) for control or computation

Examples of BRAIN

1. Scientists are learning more about how the human brain works.
2. The left and right sides of the brain have different functions.
3. The other children always teased him about being such a brain.

Illustration of BRAIN

Origin of BRAIN

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: before 12th century

Related to BRAIN

Synonyms

genius, brainiac, intellect, thinker, whiz, wiz, wizard

Antonyms

blockhead, dodo, dolt, dope, dumbbell, dummy, dunce, fathead, goon, half-wit, hammerhead, idiot, imbecile, knucklehead, moron, nitwit, numskull (or numbskull), pinhead

Related Words

polyhistor, polymath, Renaissance man; blue, bluestocking, highbrow, intellectual; sage, savant; egghead, geek, longhair, nerd; master, virtuoso; ace, crackerjack (also crackajack), natural

Near Antonyms

ignoramus, illiterate, know-nothing, lowbrow; anti-intellectual, philistine; ass, donkey, fool, jackass; beast, boor, cad, churl, clown, creep, cretin, cur, heel, jerk, louse, lout, skunk, snake, stinker

Other Anatomy Terms

bilateral symmetry, carotid, cartilage, dorsal, entrails, prehensile, renal, solar plexus, supine, thoracic, ventral

Rhymes with BRAIN

ain, Aisne, ane, Bain, bane, blain, cane, chain, crane, deign, drain, fain, fane, feign, gain, grain, Kane, lane, Lane, main, mane, pain, Paine, pane, plain, plane, quean, rain, reign, rein, sain, sane, seine, Seine, skein, Spain, sprain, stain, strain, swain, thane, thegn, train, twain, Twain, vain, vane, vein, wain, wane, Wayne

²brain

transitive verb

Definition of BRAIN

1

: to kill by smashing the skull

2

: to hit on the head

Examples of BRAIN

1. The tree limb fell and nearly brained me.

First Known Use of BRAIN

14th century

brain

noun \ˈbrān\   (Medical Dictionary)

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

Illustration of BRAIN

brain

noun    (Concise Encyclopedia)

Side view of the brain showing its major structures. The large cerebrum is divided into two halves, …—© Merriam-Webster Inc.

Concentration of nerve tissue in the front or upper end of an animal's body. It handles sensory information, controls motion, is vital to instinctive acts, and in higher vertebrates is the centre of learning. Vertebrate brains consist of the hindbrain (rhombencephalon), midbrain (mesencephalon), and forebrain (prosencephalon). The hindbrain comprises the medulla oblongata and the pons, which connects the spinal cord with higher brain levels and transfers information from the cerebral cortex to the cerebellum. The midbrain, a major sensory integration centre in other vertebrates, serves primarily to link the hindbrain and forebrain in mammals. Large nerve bundles connect the cerebellum to the medulla, pons, and midbrain. In the forebrain the two cerebral hemispheres are connected by a thick bundle of nerve fibres (corpus callosum) and are divided by two deep grooves into four lobes (frontal, parietal, temporal, and occipital). The cerebrum, the largest part of the human brain, is involved with its more complex functions. Motor and sensory nerve fibres from each hemisphere cross over in the medulla to control the opposite side of the body.