Definitions of campaign:

• noun:   an overland journey by hunters (especially in Africa)
• noun:   a series of actions advancing a principle or tending toward a particular end

  Example: "He supported populist campaigns"

• noun:   several related operations aimed at achieving a particular goal (usually within geographical and temporal constraints)
• noun:   a race between candidates for elective office

  Example: "I managed his campaign for governor"

• verb:   go on a campaign; go off to war
• verb:   run, stand, or compete for an office or a position
• verb:   exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for