firewall

From fire +‎ wall. Compare West Frisian brânmuorre, Dutch brandmuur, German Brandmauer, Feuermauer, Swedish brandvägg, brandmur, Icelandic eldvegg. The verb sense for using maximum power or acceleration comes from the engine's firewall being the limit of forward movement of the throttle controls on many simpler vehicles; thus, to get the maximum engine output, one would push the throttle levers or pedal all the way to the firewall. The politics sense is a calque of German Brandmauer.

• (UK) IPA^(key): /ˈfaɪə.wɔəl/
• (UK) IPA^(key): /ˈfaɪ.əˌwɔːl/
• (US) IPA^(key): /ˈfaɪ(ə)ɹˌwɔl/, /ˈfaɪ(ə)ɹˌwɑl/

• Audio (US):

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• Audio (Canada):

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firewall (plural firewalls)

2. (architecture) A fireproof barrier used to prevent the spread of fire between or through buildings, structures, electrical substation transformers, or within an aircraft or vehicle.

   Coordinate terms: firestop, fire block; bulkhead

4. (computer security) The software that monitors traffic in and out of a private network or a personal computer and allows or blocks such traffic depending on its perceived threat.
6. (physics) A hypothetical phenomenon where an observer falling into a black hole encounters high-energy quanta at or near the event horizon.
8. An ethical wall; an organizational or legal separation between two entities that might otherwise cause conflicts of interest.
   • 2017 July 6, Jeremy Harris Lipschultz, Social Media Communication: Concepts, Practices, Data, Law and Ethics, Taylor & Francis, →ISBN, page 275:

     The book explains this in Adam Hochberg's (@adamhochberg) chapter discussing the Wisconsin Center for Investigative Journalism's concerns related to non-profit news organizations: donor transparency, editorial independence, the firewall between journalism and fundraising, and conflicts of interest.

10. (politics, especially Germany) An unwritten agreement among major political parties to refuse to govern or cooperate with national conservative and ultranationalist parties.
    • 2025 January 12, James Crisp, Meike Eijsberg, “The great firewall keeping out the hard-Right collapses across Europe”, in Chris Evans, editor, The Daily Telegraph‎^[1], London: Telegraph Media Group, →ISSN, →OCLC, archived from the original on 12 January 2025:

      "Honest government must be preceded by honest negotiations," Mr Kickl said when Austria's president tasked him with beginning coalition talks after the centrist firewall failed.

    • 2025 February 14, Jim Tankersley, Steven Erlanger, David E. Sanger, “Vance Tells Europeans to Stop Shunning Parties Deemed Extreme”, in The New York Times‎^[2], New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 15 February 2025:

      Other firewalls have fallen around Europe, including in the Netherlands, Hungary and Italy. In Austria, the hard-right Freedom Party has been part of federal coalitions and appeared set to lead its next government, before negotiations with a center-right party collapsed this week.

    • 2026 January 30, Marc Felix Serrao, “Germany's Far Right Is on the Threshold of Power. This Man Is Leading the Charge.”, in Politico‎^[3], archived from the original on 31 January 2026:

      Most of the time, German parties come to power in states and nationally by forming coalitions. As long as the firewall holds, the only way the AfD can take power is by winning a straight-up majority. Which is what it seems poised to do in the September elections.

• Great Firewall of China, Chinese firewall

firewall (third-person singular simple present firewalls, present participle firewalling, simple past and past participle firewalled)

1. (transitive, computer security) To protect with a firewall.
2. (transitive, computer security) To block with a firewall.
3. (intransitive, motor vehicles or aircraft, slang) To use maximum engine power or acceleration.

• firewall on Wikipedia.Wikipedia
• firewall (construction) on Wikipedia.Wikipedia
• firewall against the far-right in Germany on Wikipedia.Wikipedia

Unadapted borrowing from English firewall.

• IPA^(key): [ˈfajr̩voːl]

firewall m inan

1. (computing) firewall

• “firewall”, in Internetová jazyková příručka (in Czech), 2008–2026

Unadapted borrowing from English firewall.

• IPA^(key): /ˈfajr.wol/

firewall m (invariable)

1. (computer security) firewall (computer software that monitors traffic in a network)

Unadapted borrowing from English firewall.

• Hyphenation: fi‧re‧wall

firewall m or f (plural firewalls)

1. (computer security) firewall (computer software that monitors traffic in a network)

• “firewall”, in Dicionário Aulete Digital (in Portuguese), Rio de Janeiro: Lexikon Editora Digital, 2008–2026

Unadapted borrowing from English firewall.

• IPA^(key): /fajeɾˈwal/ [fa.jeɾˈwal]
• IPA^(key): /fajeɾˈw̝al/ [fa.jeɾˈw̝al]
• Rhymes: -al

firewall m (plural firewalls)

1. (computing) firewall

   Synonym: cortafuegos

According to Royal Spanish Academy (RAE) prescriptions, unadapted foreign words should be written in italics in a text printed in roman type, and vice versa, and in quotation marks in a manuscript text or when italics are not available. In practice, this RAE prescription is not always followed.