# firewall

/ˈfaɪɹwɑɫ/ (US) · /fˈaɪəwɔːl/ (UK)

Source: https://englishreference.com/word/firewall
Updated: 2026-08-27

## Senses

### 1. computing security

noun · CEFR B2

software or hardware that protects a computer network by blocking dangerous traffic from the internet.

For teachers: a security system consisting of software or hardware that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

- You should update your firewall to protect your computer from the latest viruses.
- The corporate firewall blocked the suspicious connection attempt before the malware could infiltrate the internal server.

Usage: Often used with the verbs 'set up', 'configure', or 'bypass'.

### 2. fire protection

noun · CEFR C1 · Technical

a wall made of special materials that stops a fire from moving from one part of a building to another.

For teachers: a fireproof barrier designed to prevent the spread of fire between or through buildings, structures, or vehicles.

- The warehouse was saved because the firewall stopped the flames from reaching the office.
- Building regulations require a reinforced firewall between the garage and the living quarters to ensure resident safety in the event of a vehicle fire.

### 3. political/ethical barrier

noun · CEFR C1 · Formal

a rule or agreement that keeps two groups apart to prevent a conflict of interest or bad influence.

For teachers: a metaphorical barrier or ethical wall established to prevent communication or cooperation between entities, often to avoid conflicts of interest.

- The company created a firewall between the two departments to keep client information private.
- The mainstream parties maintained a political firewall, refusing to enter into any coalition agreements with the extremist faction.

### 4. to protect or block

verb · CEFR C1 · Technical

to protect a system using a firewall or to block a specific connection.

For teachers: to protect a network or device with a firewall; to isolate a segment of a system for security purposes.

- The IT department decided to firewall the sensitive database from the rest of the office network.
- By firewalling the guest Wi-Fi, the administrator ensured that visitors could not access the company's internal files.

### 5. to go full speed

verb · CEFR C2 · Slang · Informal

to use the maximum power of an engine or to drive as fast as possible.

For teachers: to operate an engine at maximum throttle or to accelerate a vehicle to its limit.

- He decided to firewall the car on the open highway to see how fast it could go.
- The pilot had to firewall the engines to clear the ridge during the emergency ascent.

Teaching tip: This sense is highly informal and specific to automotive or aviation contexts; most learners will only encounter the computing sense.

## Examples

- You should always keep your firewall turned on.
- The company's firewall blocked the suspicious login attempt from an unknown server in another country.
- Advanced firewalls use deep packet inspection to identify and neutralize sophisticated threats that might bypass simpler filtering systems by masquerading as legitimate data traffic.

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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.