troops in Aleppo during WW1.]]A troop is a military unit, originally a small force of cavalry, subordinate to a squadron and headed by the troop leader. Cavalry soldiers of private rank are called troopers (abbreviated Tpr., not troupers). Today, troop has different specific meanings in different armed forces. Generally, soldiers may be referred to as troops. British Army and Royal Marines In the British Army the definition of a troop varies by corps. · Household Cavalry and Royal Armoured Corps: Three or four armoured fighting vehicles commanded by a subaltern. A unit of two to four guns or launchers, or an equivalent headquarters unit. In the Royal Horse Artillery, a troop used to be the equivalent to a battery in other artillery units. · Royal Engineers, Royal Corps of Signals and Royal Logistic Corps: A unit equivalent in size to a platoon in