WAR (noun).

1. a conflict carried on by force of arms, as between nations or between parties within a nation; warfare, as by land, sea, or air.
2. a state or period of armed hostility or active military operations: The two nations were at war with each other.
3. a contest carried on by force of arms, as in a series of battles or campaigns: the War of 1812.
4. active hostility or contention; conflict; contest: a war of words.
5. aggressive business conflict, as through severe price cutting in the same industry or any other means of undermining competitors: a fare war among airlines; a trade war between nations.
6. a struggle: a war for men's minds; a war against poverty.
7. armed fighting, as a science, profession, activity, or art; methods or principles of waging armed conflict: War is the soldier's business.

* Excerpted from the Random House Webster's Unabridged Dictionary 3.0.