Etymology

Noun

1. The control center of the central nervous system of an animal located in the skull which is responsible for perception, cognition, attention, memory, emotion, and action.
2. An intelligent person.

   He was a total brain.

3. A person who provides the intelligence required for something.

   He is the brains behind the scheme.

4. (in plural brains) Intellect.

   He has a lot of brains.

5. By analogy with a human brain, the part of a machine or computer that performs calculations.

   The computer's brain is capable of millions of calculations a second.

Verb

1. To strike (someone) on the head.
2. To kill (a person) by smashing that person's skull.