I. brain 1 S2 W2 /breɪn/ BrE AmE noun
[ Language: Old English ; Origin: brægen ]
1 . ORGAN [countable] the organ inside your head that controls how you think, feel, and move:
Messages from the brain are carried by the central nervous system.
the chemistry of the brain
the human brain
the right/left hemisphere of the brain (=the right or left side of the brain)
Emotional responses are a function of the right hemisphere of the brain.
She died of a brain tumour.
brain tissue/cell
2 . INTELLIGENCE [countable usually plural, uncountable] the ability to think clearly and learn quickly:
If you had any brains, you’d know what I meant.
The job requires brains.
Something’s addled your brains (=made you confused) .
Come on, use your brain, John.
3 . PERSON [countable usually plural] informal someone who is intelligent, with good ideas and useful skills:
Some of our best brains are leaving the country to work in the US.
⇨ ↑ brain drain
4 . FOOD [uncountable] ( also brains [plural] ) the brain of an animal, used as food
5 . have something on the brain informal to be always thinking about something:
I’ve got that song on the brain today.
6 . be the brains behind/of something to be the person who thought of and developed a particular plan, system, or organization, especially a successful one:
Danny’s definitely the brains of the project.
7 . brain dead
a) in a state where your brain has stopped working properly, even though your heart may still be beating
b) informal in a state in which you seem stupid or uninteresting, especially because you live a boring life or are very tired
8 . something is not brain surgery informal used to say that something is not difficult to do
⇨ ↑ bird-brain , ↑ hare-brained , ⇨ beat your brains out at ↑ beat 1 (22), ⇨ pick sb’s brains at ↑ pick 1 (7), ⇨ rack your brain(s) at ↑ rack 2 (2)
• • •
COLLOCATIONS (for Meaning 2)
■ verbs
▪ have brains
You should have more brains than to smoke.
▪ use your brain
It’s easy if you just use your brain.
▪ rack your brains (=try very hard to think of something)
If we all rack our brains we should come up with some ideas.
▪ pick sb’s brains (=ask someone for ideas)
I thought I’d pick Greg's brains about what to take with us.
▪ it takes/requires brains to do something
It takes brains to think of a plan like that.
▪ something addles your brain (=makes you unable to think clearly)
The alcohol had addled his brain.
■ adjectives
▪ a good/quick brain
It was obvious that Ann had a good brain.
II. brain 2 BrE AmE verb [transitive] informal
to hit someone very hard on the head – used humorously:
I wanted to brain him.