# brain

/ˈbɹeɪn/ (US) · /bɹˈeɪn/ (UK)

Source: https://englishreference.com/word/brain
Updated: 2026-06-19

## Senses

### 1. the organ

noun · CEFR A2

the organ inside your head that controls your body, thoughts, and feelings.

For teachers: the primary organ of the central nervous system in the skull, responsible for cognition, memory, and motor control.

- The human brain uses a lot of energy even when you are sleeping.
- Neuroscientists are still mapping the complex neural pathways within the human brain to understand how memory is stored.

### 2. intelligence

noun · CEFR B1

your ability to think, learn, and solve problems.

For teachers: intellectual capacity or mental ability; often used in the plural to refer to high intelligence.

- She has the brains to become a doctor if she works hard.
- It took a lot of brains to figure out the logistics of moving the entire office over a single weekend.

Usage: Often used in the plural form 'brains' when referring to general intelligence.

### 3. a smart person

noun · CEFR B2 · Informal

a person who is very intelligent.

For teachers: a highly intelligent person, often one who provides the intellectual leadership for a project.

- Ask Sarah for help with the math homework; she is the brain of the class.
- He was known as the brain behind the operation, coordinating every technical detail from the home office.

### 4. computer control center

noun · CEFR B2

the part of a machine or computer that does the thinking and calculations.

For teachers: the central processing unit or control mechanism of a machine, likened to a biological brain.

- The computer's brain was damaged when the coffee spilled on the desk.
- The onboard computer serves as the brain of the spacecraft, managing life support and navigation systems simultaneously.

### 5. to hit on the head

verb · CEFR C2 · Informal

to hit someone very hard on the head.

For teachers: to strike someone forcefully on the head; historically, to kill by smashing the skull.

- The cartoon character tried to brain the giant with a large wooden hammer.
- In the old adventure novel, the hero nearly got brained by a falling rock while escaping the cave.

Usage: This verb is transitive and requires a direct object.

Teaching tip: This is quite violent and informal; it is often used in a slightly exaggerated or humorous way in modern speech.

## Examples

- The brain needs plenty of sleep to function well.
- Scientists are still working to understand how the human brain stores long-term memories.
- Neuroplasticity allows the brain to reorganize its neural pathways in response to new experiences or after a traumatic injury.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.