Other forms: brains
The brain is the organ in your head that thinks and remembers. Use your brain, brain damage, the human brain.
It has about eighty-six billion neurons and uses roughly a fifth of the body's energy while weighing about a fiftieth of it. Brains in the plural means intelligence: he has brains. The idioms are many: rack your brains, pick somebody's brains, brain drain, and the brains behind an operation. Note brainstorm, brainwave; and that most confident statements about which side of the brain does what are wrong.
1nounbrainThe organ in your head that thinks and remembers.~98%
“The brain uses about a fifth of everything you eat.”
2nounintelligenceIntelligence.~2%
“She's got the brains to become a doctor if she works hard.”
Shares are an estimate: a language model read 12 sentences found in the wild and placed 12 of them on a sense — a count of our sample, not a measurement of English.
brain is an organ, or intelligence.
Old English braegen is Germanic and its deeper root is uncertain. Latin used cerebrum, which gives cerebral, so English again has a plain native word and a borrowed technical one side by side.
Middle English
brayn
English, today
brain
From Middle English brayn. Cognate with Scots braine, brane (“brain”), frr brayen, brein, Brain (“brain”), stq Brainge, Bräienge (“brain”), West Frisian brein (“brain”), Dutch brein (“brain”), Low German Brägen, Bregen (“brain”) (whence German Bregen (“animal brain”)), Ancient Greek βρεχμός (“front part of the skull, top of the head”).
Etymology from Wiktionary, CC BY-SA