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from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. An act or event that provokes or is used to justify war.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. An act seen as justifying or causing a war.
  • n. Plural form of casus belli.

from the GNU version of the Collaborative International Dictionary of English

  • n. an event or combination of events which is a cause war, or may be alleged as a justification of war.

from The Century Dictionary and Cyclopedia

  • n. A matter or occasion of war; an excuse or a reason for declaring war: as, the right of search claimed by Great Britain constituted a casus belli in 1812.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an event used to justify starting a war


New Latin cāsus bellī : Latin cāsus, occasion + Latin bellī, genitive of bellum, war.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin casus ("case") + belli ("of war"). (Wiktionary)


  • Not because the casus belli for the war was that they oppress their women–but rather that the same medieval attitudes that led them to oppress women and behead people also led them to hate and kill us in the first place.

    The Volokh Conspiracy » 300 Years Behind the Times


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