Definition of "War" :

noun: a concerted campaign to end something that is injurious

"The war on poverty."

noun: the waging of armed conflict against an enemy

"Thousands of people were killed in the war."

noun: an active struggle between competing entities

"A price war."

noun: a legal state created by a declaration of war and ended by official declaration during which the international rules of war apply

"War was declared in November but actual fighting did not begin until the following spring."

verb: make or wage war