Noun

• S: (n) lookout, lookout man, sentinel, sentry, watch, spotter, scout, picket (a person employed to keep watch for some anticipated event)
• S: (n) picket (a detachment of troops guarding an army from surprise attack)
• S: (n) picket (a protester posted by a labor organization outside a place of work)
• S: (n) picket (a vehicle performing sentinel duty)
• S: (n) picket, pale (a wooden strip forming part of a fence)
• S: (n) picket, piquet (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)

Verb

• S: (v) picket (serve as pickets or post pickets) "picket a business to protest the layoffs"
• S: (v) picket (fasten with a picket) "picket the goat"