A campaign is a phase of a war involving a series of operations related in time and space and aimed towards a single, specific, strategic objective or lead to the war. A campaign may add a single battle, but more often it comprises a number of battles over a long-drawn-out time period or a considerable distance, but within a single theatre of operations or delimited area. A campaign may last only a couple of weeks, but usually lasts a few months or even a year.
The term derives from the plain of Campania when it was a location of annual wartime operations by the armies of the Roman Republic. Many historical campaigns are so named as misnomers to improve or reduce the perception of operations for other than military reasons.
A military campaign denotes the time during which a given military force conducts fight operations in a particular area (often mentioned as AO, area of operation). A military campaign can be executed by either a single Armed Service, or as a combined services campaign conducted by land, naval, air and space forces. It is conducted with the function of accomplishing a certain desired resolution of a military conflict as its strategic goal, usually within a clearly defined resource, geographic and time limited criteria.