firewall

IPA/ˈfaɪəwɔːl/
KK[fˈaɪrwɑl]IPA/ˈfaɪərwɔːl/

firewall — noun

  • firewallsingular
  • firewallsplural

1. a hardware device or software program that checks data moving between a computer

1.nounB1
Definition

a hardware device or software program that checks data moving between a computer or network and the internet, blocking anything it decides is dangerous or unauthorised

Example

Amihan installed a firewall on her laptop before using the public Wi-Fi at a café.

real-world scenario: public Wi-Fi safety

The company's firewall blocked an attempt to access its internal files from an unknown address.

passive construction: firewall blocked [attempt]

Common collocations
  • firewall rules
  • configure a firewall
  • bypass the firewall
  • firewall protection
  • corporate firewall
  • breach the firewall
Synonyms
  • security system

    broader term that includes firewalls, antivirus tools, and other protective measures

  • proxy

    a type of server that can act as a firewall by filtering traffic between a network and the internet

Usage Note

The computing sense is by far the most common meaning of 'firewall' in modern English. Learners at B1 level should learn this sense first — it appears frequently in workplace, academic, and general technology contexts.

Common Mistakes

The firewall blocked the virus from entering my computer.
The firewall blocked the unauthorised connection attempt.
A firewall controls access and data traffic; it does not directly detect or block viruses. Antivirus software handles that role.

2. a wall made of fire-resistant material that divides a building or vehicle into s

2.nounB2
Definition

a wall made of fire-resistant material that divides a building or vehicle into sections, so that a fire cannot easily spread from one part to another

Example

The apartment building has a fireproof firewall between each unit to slow any flames.

Building codes require a firewall between the garage and the main house in many countries.

collocation: building codes require a firewall

Common collocations
  • firewall between buildings
  • fire-rated firewall
  • firewall regulations
  • install a firewall
  • fire-resistant firewall
Synonyms
  • fire barrier

    a more general term for any material or structure that stops fire from spreading

  • fire door

    a specific type of fire-rated door, not a wall, but serves a similar purpose

Usage Note

This is the original, physical meaning of 'firewall'. It is much less common than the computing sense but remains standard in construction, architecture, and vehicle-safety contexts.