Troop,

Chambers's Encyclopaedia, Volume 10: Swastika to Zyrianovsk and Index, p. 303

Troop, in Cavalry, a captain's command, consisting in the British army of two lieutenants, fifty-six mounted non-commissioned officers and troopers, and some twenty dismounted men when the regiment is at war strength. Two troops form a squadron, which is the manoeuvring unit.

Source scan(s): p. 0322