Troop  —n. 1 assembled company; assemblage of people or animals. 2 (in pl.) Soldiers, armed forces. 3 cavalry unit under a captain. 4 unit of artillery or armoured vehicles. 5 grouping of three or more scout patrols. —v. (foll. By in, out, off, etc.) Come together or move in large numbers.  troop the colour transfer a flag ceremonially at a public mounting of garrison guards. [french troupe]