Patrol

Definition:

(v. i.) To go the rounds along a chain of sentinels; to traverse a police district or beat.
(v.) t To go the rounds of, as a sentry, guard, or policeman; as, to patrol a frontier; to patrol a beat.
(v. i.) A going of the rounds along the chain of sentinels and between the posts, by a guard, usually consisting of three or four men, to insure greater security from attacks on the outposts.
(v. i.) A movement, by a small body of troops beyond the line of outposts, to explore the country and gain intelligence of the enemy's whereabouts.
(v. i.) The guard or men who go the rounds for observation; a detachment whose duty it is to patrol.
(v. i.) Any perambulation of a particular line or district to guard it; also, the men thus guarding; as, a customs patrol; a fire patrol.

Compare patrol with other words:

parol vs. patrol