Etymology 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.
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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.
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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.
Computer security
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Natural sciences, Physical sciences, Physics A hypothetical phenomenon where an observer falling into a black hole encounters high-energy quanta at or near the event horizon.
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An ethical wall; an organizational or legal separation between two entities that might otherwise cause conflicts of interest.
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.2017 July 6, Jeremy Harris Lipschultz, Social Media Communication: Concepts, Practices, Data, Law and Ethics, Taylor & Francis, →ISBN, page 275:
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Government, PoliticsGermany, Especially An unwritten agreement among major political parties to refuse to govern or cooperate with national conservative and ultranationalist parties.
"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 January 12, James Crisp, Meike Eijsberg, “The great firewall keeping out the hard-Right collapses across Europe”, in Chris Evans, editor, The Daily Telegraph, London: Telegraph Media Group, →ISSN, →OCLC, archived from the original on 12 Jan 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.2025 February 14, Jim Tankersley, Steven Erlanger, David E. Sanger, “Vance Tells Europeans to Stop Shunning Parties Deemed Extreme”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 15 Feb 2025:
1 more example
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.2026 January 30, Marc Felix Serrao, “Germany's Far Right Is on the Threshold of Power. This Man Is Leading the Charge.”, in Politico, archived from the original on 31 Jan 2026:
Derived terms
Great Firewall of China, Chinese firewall
firewall
verb
Etymology 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.
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To protect with a firewall.
Computer security
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To block with a firewall.
Computer security
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Slang To use maximum engine power or acceleration.