firewall

American  

[fahyuhr-wawl] / ˈfaɪərˌwɔl /

Or fire wall

noun

• firewalls
  plural

1. a partition made of fireproof material to prevent the spread of a fire from one part of a building or ship to another or to isolate an engine compartment, as on a plane, automobile, etc.

2. a person, thing, or event that acts as a barrier or protection against something undesirable.

   The new employee handbook should create a firewall against unethical business conduct.

3. Digital Technology. an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system.

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firewall British  

noun

1. a fireproof wall or partition used to impede the progress of a fire, as from one room or compartment to another

2. computing a computer system that isolates another computer from the internet in order to prevent unauthorized access

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firewall Scientific  

/ fîr′wôl′ /

1. A software program or hardware device that restricts communication between a private network or computer system and outside networks.

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firewall Cultural  

1. A means of separating a computer network from outside networks for security purposes. A server outside an organization's own network may be used to funnel all incoming and outgoing traffic to assist in keeping out viruses, as well as to prevent unauthorized outsiders from gaining access to a network.

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Other Word Forms

Noun Inflected Forms

• firewalls
  plural

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Etymology

Origin of firewall

An Americanism dating back to 1750–60

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Explanation

A sturdy barrier that's flame resistant is called a firewall. Another kind of firewall is the one a computer system uses to block potentially dangerous external networks or hackers. The original firewall was exactly what it sounds like: a wall that provides a safe barrier against fire. These firewalls are often used in large buildings (or between structures that are connected) to prevent a fire from spreading once it's started. The term was borrowed to describe something in computing that plays a similar role, limiting the access to a network, usually from the internet. Your firewall helps protect your computer against viruses and malware.

Example Sentences

See Examples For:

firewall firewalls

In 2020, I calculated that repealing the firewall would lead to $2.2 trillion in higher subsidy spending over a decade for the estimated 24 million people who would switch from employer coverage to the exchanges.

From The Wall Street Journal ● Aug. 11, 2026

The roles overlapped, but Robb and the mayor’s office insisted there was a firewall between Robb and the mayor regarding the Lineage fire.

From Los Angeles Times ● Aug. 2, 2026

Following the latest revelations, historian David Olusoga told BBC Newsnight there is now "a desperate desire within government and within the palace to draw a firewall… between this crisis and the wider monarchy".

From BBC ● Feb. 21, 2026

Meanwhile, Morgan Stanley analyst Meta Marshall wrote of “continued momentum and firewall share gains” that may have driven Palo Alto Networks’ revenue above the 17% to 18% growth rate that the company had projected.

From MarketWatch ● Feb. 17, 2026

I torched through the firewall, maybe five seconds.

From "Burning Blue" by Paul Griffin

"You can build a vault with mathematical firewalls, but if the individual holding the keys can be duped, the vault is opened," said Dr Clive Summerfield, head of FARx, a biometrics in AI security company.

From BBC ● Oct. 30, 2026

Product revenue in Fortinet’s case refers to firewalls and broader secure-networking hardware offerings.

From MarketWatch ● Oct. 28, 2026

Normally when hacks happen, the evidence lies hidden behind corporate firewalls, but the swarms tracked by Piecha and others left traces of their activities scattered all over the internet—sometimes intentionally, to help each other.

From The Wall Street Journal ● Oct. 2, 2026

Earlier this year, Amazon discovered that a low-skilled hacker used commercially available AI to breach 600 firewalls.

From Los Angeles Times ● Mar. 5, 2026

Then, last night, just before I’d succumbed to exhaustion, I’d finally managed to navigate my way through the intranet’s labyrinth of firewalls and into the main Oology Division database.

From "Ready Player One: A Novel" by Ernest Cline

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