Noun

1. A person employed to keep watch for some anticipated event
2. A detachment of troops guarding an army from surprise attack
3. A protester posted by a labor organization outside a place of work
4. A vehicle performing sentinel duty
5. A wooden strip forming part of a fence
6. 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

1. Serve as pickets or post pickets
2. Fasten with a picket