I. noun
Etymology: rear (V) + vault (arched structure); translation of French arrière-voussure
: a rear arch used where a wall is very thick and the window recess becomes a vaulted area
II. noun
Etymology: rear (V) + vault (leap)
: a vault in which the body is raised sideward to either right or left and then rotated a quarter turn outward so that the back of the body passes over the apparatus used