Complex sentence: In the British Army the term "cavalry" was only used for regular army units, and the other mounted regiments in the army, which were part of the Territorial Force reserve, were the fifty-five yeomanry regiments and three special reserve regiments of horse.
Split into simpler sentences: In the British Army the term "cavalry" was only used for regular army units. The other mounted regiments in the army, which were part of the Territorial Force reserve, were the fifty-five yeomanry regiments and three special reserve regiments of horse.