War
War is a state of total conflict. Often within a historical context, wars have been geopolitical events between two entities, often states. Weapons may be used as a tool in war.
Wars have been waged through human history.
Recently, the dynamics of war have shifted from the traditional dynamics of two well defined entities against one another to the dynamics of being "asymmetrical". That is, now, it may be that there is an ideology or loose collection of people which is up against a state. This has forced a dramatic change in tactics.