patrol
pa·trol / pəˈtrōl/ • n. a person or group of people sent to keep watch over an area, esp. a detachment of guards or police: a police patrol stopped the man and searched him. ∎ the action of keeping watch over an area by walking or driving around it at regular intervals: the policemen were on patrol when they were ordered to investigate the incident. ∎ an expedition to carry out reconnaissance: we were ordered to investigate on a night patrol. ∎ a detachment of troops sent out to reconnoiter: you couldn't go through the country without meeting an enemy patrol. ∎ a routine operational voyage of a ship or aircraft: a submarine patrol. ∎ a unit of six to eight Girl Scouts or Boy Scouts forming part of a troop.• v. (-trolled, -trol·ling) [tr.] keep watch over (an area) by regularly walking or traveling around or through it: the garrison had to patrol the streets to maintain order | [intr.] pairs of men were patrolling on each side of the thoroughfare. DERIVATIVES: pa·trol·ler n.