Picket
WordNet
noun
(1) A form of military punishment used by the British in the late 17th century in which a soldier was forced to stand on one foot on a pointed stake
(2) A wooden strip forming part of a fence
(3) A vehicle performing sentinel duty
(4) A detachment of troops guarding an army from surprise attack
(5) A person employed to watch for something to happen
(6) A protester posted by a labor organization outside a place of work
verb
(7) Fasten with a picket
"Picket the goat"
(8) Serve as pickets or post pickets
"Picket a business to protest the layoffs"