- The definition of a brain is the mass of nerve tissue located in the head of animals with spinal cords; it is the center of thought and controls movement.
An example of brain is what is damaged when someone has Alzheimer's disease.
- A brain is defined as a smart or intellectual person.
An example of brain is a student who is valedictorian of their class.
A model of the human brain.
brain definition by Webster's New World
- the mass of nerve tissue in the cranium of vertebrate animals, an enlarged extension of the spinal cord: it is the main part of the nervous system, the center of thought, and the organ that perceives sensory impulses and regulates motor impulses: it is made up of gray matter (the outer cortex of nerve cells) and white matter (the inner mass of nerve fibers)
- a comparable organ in invertebrate animals
- intelligence; mental ability
- Informal a person of great intelligence
- Informal the main organizer or planner of a group activity; chief controller or director
Origin: Middle English ; from Old English brægen ; from Indo-European base an unverified form mregh-m(n)o-, skull, brain from source Classical Greek bregma, forehead
- to dash out the brains of
- Slang to hit hard on the head
brain definition by American Heritage Dictionary
- a. The portion of the vertebrate central nervous system that is enclosed within the cranium, continuous with the spinal cord, and composed of gray matter and white matter. It is the primary center for the regulation and control of bodily activities, receiving and interpreting sensory impulses, and transmitting information to the muscles and body organs. It is also the seat of consciousness, thought, memory, and emotion.b. A functionally similar portion of the invertebrate nervous system.
- a. Intellectual ability; mind: a dull brain; a quick brain.b. Intellectual power; intelligence. Often used in the plural: has brains and good looks. See Synonyms at mind.
- A highly intelligent person.
- The primary director or planner, as of an organization or movement. Often used in the plural.
- The control center, as of a ship, aircraft, or spacecraft.
- To smash in the skull of.
- To hit on the head.
Origin: Middle English, from Old English brǽgen.
brainA. pituitary gland B. cerebrum C. skull D. corpus callosum E. thalamus F. hypothalamus G. pons H. cerebellum I. medulla J. spinal cord
brain - Ologies & -Isms Definition
brain - Cultural Definition
The central organ in the nervous system, protected by the skull. The brain consists of the medulla, which sends signals from the spinal cord to the rest of the brain and also controls the autonomic nervous system; the pons, a mass of nerve fibers connected to the medulla; the cerebellum, which controls balance and coordination; and the cerebrum, the outer layer of which, the cerebral cortex, is the location of memory, sight, speech, and other higher functions.
The cerebrum contains two hemispheres (the left hemisphere and the right hemisphere), each of which controls different functions. In general, the right hemisphere controls the left side of the body and such functions as spatial perception, whereas the left hemisphere controls the right side of the body and functions such as speech.
Under the cerebral cortex are the thalamus, the main relay center between the medulla and the cerebrum; and the hypothalamus, which controls blood pressure, body temperature, hunger, thirst, sex drive, and other visceral functions.
brain - Medical Definition
brain - Phrases/Idioms
beat one's brainsor rack one's brains or cudgel one's brains
have on the brain
pick someone's brains
beat (one's) brains (out)
on the brain
rack (one's) brain
brain - Science Definition
- The part of the nervous system in vertebrates that is enclosed within the skull, is connected with the spinal cord, and is composed of gray matter and white matter. It is the control center of the central nervous system, receiving sensory impulses from the rest of the body and transmitting motor impulses for the regulation of voluntary movement. The brain also contains the centers of consciousness, thought, language, memory, and emotion. See more at brainstem, cerebellum, cerebrum.
- A bundle of nerves in many invertebrate animals that is similar to the vertebrate brain in function and position.
A. skull, B. cerebrum, C. pituitary gland, D. pons, E. thalamus, F. cerebellum, G. medulla oblongata, H. spinal cord