—n.
1 an organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating centre of sensation, and of intellectual and nervous activity.
2 (in pl.) the substance of the brain, esp. as food.
3 a a person's intellectual capacity (has a poor brain). b (often in pl.) intelligence; high intellectual capacity (has a brain; has brains).
4 (in pl.; prec. by the) colloq. a the cleverest person in a group. b a person who originates a complex plan or idea (the brains behind the robbery).
5 an electronic device with functions comparable to those of a brain.
—v.tr.
1 dash out the brains of.
2 strike hard on the head.
Phrases and idioms:
brain-dead suffering from brain death. brain death irreversible brain damage causing the end of independent respiration, regarded as indicative of death. brain drain colloq. the loss of skilled personnel by emigration. brain fever inflammation of the brain. brain-pan colloq. the skull. brain stem the central trunk of the brain, upon which the cerebrum and cerebellum are set, and which continues downwards to form the spinal cord. brains (US brain) trust a group of experts who give impromptu answers to questions, usu. publicly. brain-teaser (or -twister) colloq. a puzzle or problem. brain trust US a group of expert advisers. on the brain colloq. obsessively in one's thoughts.
Etymology: OE braeliggen f. WG
Useful english dictionary. 2012.