■ noun
1》 a person or group sent to keep watch over an area, especially a detachment of guards or police.
↘a unit of six to eight Scouts or Guides forming part of a troop.
2》 the action of ~ling an area.
3》 an expedition to carry out reconnaissance.
↘a routine operational voyage of a ship or aircraft.
■ verb ( ~s , ~ling , ~led ) keep watch over (an area) by regularly walking or travelling around it.
Derivatives
~ler noun
Origin
C17: from Ger. Patrolle , from Fr. patrouille , from patrouiller 'paddle in mud', from patte 'paw' + dialect (gad)rouille 'dirty water'.