(1):

(n.) Political operations preceding an election; a canvass.

(2):

(n.) An open field; a large, open plain without considerable hills. SeeChampaign.

(3):

(v. i.) To serve in a campaign.

(4):

(n.) The period during which a blast furnace is continuously in operation.

(5):

(n.) A connected series of military operations forming a distinct stage in a war; the time during which an army keeps the field.