brain · noun C /breɪn/
brain (IN HEAD)
A2 the organ inside your head that controls thought, memory, feelings and activity
Dictionary examples:
Doctors can measure activity in her brain.
The accident left him with permanent brain damage.
His wife died from a brain tumour.
Learner example:
He said the Martians opened his head and [did] experi[ments] with his brain. (Preliminary English Test; B1; Spanish)
brain (INTELLIGENCE)
C1 used to refer to intelligence
Dictionary examples:
That can't possibly be the right way to do it - use your brain!
He's got brains but he's too lazy to use them.
Learner example:
The whole [of] Western society already seems to be founded on computers and relying on chips, which to a certain extent has taken away our own abilities of using our brains. (Certificate in Advanced English; C1; Dutch)