firewall
gb/fˈaɪɚwɑl/ us/fˈaɪɚwɑl/
B2
English
~ 5300
Senses
0 senses
Noun
technical
B2
entity
1
Network security system blocking traffic
A tool (hardware or software) that checks and blocks network traffic to keep a computer or network safe from hackers and other online attacks.
Usage pattern:
install [a firewall] on [a computer/network]
Common mistake:
Learners sometimes confuse a "firewall" with "antivirus" software. A firewall mainly controls network traffic, while antivirus software looks for malicious programs already on the computer. Some learners also think "firewall" is always hardware, but it can be software as well.
Synonyms
network security system (More general; can include many tools, while a firewall is one specific type of security tool for network traffic.)
Antonyms
open network (A network with little or no protection, where traffic is not filtered or blocked.)
Collocations
install a firewall
|configure the firewall
|firewall settings
|hardware firewall
|software firewall
|firewall rules
Themes
technology
|security
|internet
Examples
- The company installed a new firewall to protect its servers from cyberattacks.
- Make sure your firewall is turned on before connecting to public Wi‑Fi.
- The IT team updated the firewall rules to block suspicious IP addresses.
- A misconfigured firewall can accidentally block legitimate traffic to your website.
- Most home routers now include a built-in firewall for basic protection.
Learner examples
- You should use a firewall on your computer at home.
- The firewall blocks bad traffic from the internet.
- Our office has a firewall to keep our data safe.
- He asked IT to check the firewall settings.
- My laptop firewall stopped a dangerous program.
Noun
C1
entity
2
Fire-resistant wall in a structure
A strong wall made with special materials that stops a fire from moving from one part of a building or vehicle to another part.
Usage pattern:
build [a firewall] between [areas]
Common mistake:
Learners often only know the computer meaning and may not realize that "firewall" is also a physical wall in buildings or vehicles. In this meaning, it is usually used in technical or safety discussions about construction, not about computers.
Synonyms
fire barrier (Very close in meaning; may refer to any construction element that blocks fire, while "firewall" is usually a full wall.)
Antonyms
open passage (An opening or area without a fire-resistant barrier, allowing fire to spread more easily.)
Collocations
build a firewall
|firewall between units
|concrete firewall
|firewall requirements
|firewall rating
Themes
construction
|safety
|housing
Examples
- Building codes require a firewall between the garage and the main house.
- A concrete firewall separates the two apartment blocks to slow the spread of any fire.
- The architect added a firewall to meet new safety regulations.
- The warehouse is divided by firewalls to protect different storage areas.
- The car’s firewall protects the passenger cabin from engine fires.
Learner examples
- The house has a firewall between the kitchen and the garage.
- They built a firewall to make the building safer.
- A firewall can stop a fire from moving to the next room.
- There is a firewall between the two apartments.
- The factory must have a firewall by law.
Noun
formal
C1
relation
3
Barrier separating groups or activities
A strong rule or separation that stops information or power from moving between two groups, usually to avoid a conflict of interest or unfair influence.
Usage pattern:
create [a firewall] between [activities/groups]
Common mistake:
Learners may incorrectly think this use always refers to computers. In formal writing about business, media, or politics, "firewall" often means an abstract separation, not a technical device. It is not used for everyday personal boundaries; words like "boundary" or "line" are more natural there.
Synonyms
barrier (More general; can be physical or social, while "firewall" in this sense usually suggests a formal, strict separation.)
Antonyms
overlap (When roles, activities, or interests mix instead of being kept strictly separate by a firewall.)
Collocations
create a firewall
|maintain a firewall
|regulatory firewall
|legal firewall
|a firewall between X and Y
Themes
business
|politics
|law
Examples
- Editors insist on a strict firewall between the news and advertising departments.
- The new regulations aim to create a firewall between investment banking and retail banking.
- We need a policy firewall to separate political donations from policy decisions.
- The company maintains a firewall between its research team and its sales staff to protect sensitive data.
- The ethics committee recommended a stronger firewall between the board and the audit team.
Learner examples
- There should be a firewall between money and politics.
- The company created a firewall between sales and research.
- They want a legal firewall between these two business areas.
- The newspaper keeps a firewall between news and ads.
- The rules build a firewall between personal and work interests.
Grammar
Dictionary form
firewall
IPA
GB/fˈaɪɚwɑl/
US/fˈaɪɚwɑl/
Syllables & stress
fire - wall (2 syllables)
Stress on 1st syllable (fire)
Word forms
Noun
- Base: firewall
- Plural: firewalls
Word family
Forms
firewalls
noun
Expressions
behind the firewall
1/bɪhˈaɪnd ðə fˈaɪɚwɑl/
fixed phrase
technical
Inside a protected internal network
Inside a private company or organization network that is protected by a firewall and not open to the public internet.
Examples
- The internal dashboard is only available behind the firewall.
- Employees can access the file server from home, but only after connecting to the VPN behind the firewall.
firewall off
1/fˈaɪɚwɑl ˈɔf/
phrasal verb
technical
Isolate a system using a firewall
To use a firewall to separate a computer or part of a network so it cannot be reached easily from other networks.
Examples
- We decided to firewall off the legacy servers from the main network.
- Sensitive lab equipment should be firewalled off from the corporate network to reduce risk.
outside the firewall
1/aʊtsˈaɪd ðə fˈaɪɚwɑl/
fixed phrase
technical
On the public internet, not internal
On the open internet, not inside a company’s protected internal network.
Examples
- The website needs to be accessible to users outside the firewall.
- Services that store sensitive data are never exposed outside the firewall.