Definitions of picket:

• noun:   a wooden strip forming part of a fence
• noun:   a vehicle performing sentinel duty
• noun:   a detachment of troops guarding an army from surprise attack
• noun:   a protester posted by a labor organization outside a place of work
• noun:   a person employed to watch for something to happen
• verb:   serve as pickets or post pickets

  Example: "Picket a business to protest the lay-offs"

• verb:   fasten with a picket

  Example: "Picket the goat"

• name:  A surname (very rare: popularity rank in the U.S.: #37154)