Wikipedia definition
1. Casus belliCasus belli is a Latin expression meaning the justification for acts of war. Casus means "incident", "rupture" or indeed "case", while belli means bellic ("of war"). It is usually distinguished from casus foederis, where casus belli refers to offenses or threats directly against a nation, and casus foederis refers to offenses or threats to another, allied, nation with which the justifying nation is engaged in a mutual defense treaty, such as NATO.
Read “Casus belli” on English Wikipedia
Read “開戦事由” on Japanese Wikipedia
Read “Casus belli” on DBpedia


to talk about this word.