picket
1. pick.et \'pik-*t\ n [F piquet, fr. MF, fr. piquer to prick - more at PIKE] 1: a pointed or sharpened stake, post, or pale 2a: a detached body of soldiers serving to guard an army from surprise 2b: a detachment kept ready in camp for such duty 2c: SENTINEL 3: a person posted by a labor organization at a place of work affected by a strike; also : a person posted for a demonstration or protest 2. picket vt 1: to enclose, fence, or fortify with pickets 2a: to guard with a picket 2b: to post as a picket 3: TETHER 4a: to post pickets at 4b: to walk or stand in front of as a picket : to serve as a picket - pick.et.er n
Webster's English Dictionary