State of conflict, generally armed, between two or more entities. It is characterized by intentional violence on the part of large bodies of individuals organized and trained for that purpose. On the national level, some wars are fought internally between rival political factions (civil war); others are fought against an external enemy. Wars have been fought in the name of religion, in self-defense, to acquire territory or resources, and to further the political aims of the aggressor state's leadership.

This entry comes from Encyclopædia Britannica Concise.
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