patrol

n. 1 act of walking or travelling around an area, esp. Regularly, for security or supervision. 2 guards, police, etc. Sent out on patrol. 3 a troops sent out to reconnoitre. B such reconnaissance. 4 unit of six to eight scouts or guides. v. (-ll-) 1 carry out a patrol of. 2 act as a patrol. [german patrolle from french]

v. i. To go the rounds along a chain of sentinels; to traverse a police district or beat.