Real Dictionary

campaign
In a war, a campaign is a series of planned movements carried out by armed forces.
countable noun: A campaign is a planned set of activities that people carry out over a period of time in order to achieve something such as social or political change.
verb: If someone campaigns for something, they carry out a planned set of activities over a period of time in order to achieve their aim.

campaign in American English
a series of military operations with a particular objective in a war
designating or of a style of simple, portable furniture, with rectilinear lines, recessed hardware, etc., originally used on military campaigns
to participate in, or go on, a campaign
intransitive verb: to serve in or go on a campaign
noun: military operations for a specific objective
transitive verb: to race (a horse, boat, car, etc.) in a number or series of competitions

campaign in British English
noun: a series of coordinated activities, such as public speaking and demonstrating, designed to achieve a social, political, or commercial goal
verb: to conduct, serve in, or go on a campaign