The whitish mass of soft matter (the center of the nervous system, and the seat of consciousness and volition) which is inclosed in the cartilaginous or bony cranium of vertebrate animals. It is simply the anterior termination of the spinal cord, and is developed from three embryonic vesicles, whose cavities are connected with the central canal of the cord; the cavities of the vesicles become the central cavities, or ventricles, and the walls thicken unequally and become the three segments, the fore-, mid-, and hind-brain.
- 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.
- A functionally similar portion of the invertebrate nervous system.
- Intellectual ability; mind: a dull brain; a quick brain.
- 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.
- Slang To smash in the skull of.
- Slang To hit on the head.
- beat (one's) brains (out) Informal To exert or expend great mental effort: She beat her brains out during the examination.
- on the brain Obsessively in mind: The coach has winning on the brain.
- brain To explore another's ideas through questioning.
- rack (one's) brain Informal To think long and hard: I racked my brain for hours trying to recall her name.