means A vault is a secure, often fortified room or container for storing valuables — or, as a verb, the act of leaping over something in one bounding motion.

from From Old French 'volte' and 'volter,' to turn or leap, rooted in Latin 'volvere,' to roll or turn. The architectural sense — a curved, arched ceiling — came from the way stones 'turn' into an arch overhead; from there it slid to mean the strong, vaulted chamber beneath. The leaping sense kept closer to the turning, twisting motion of the body in flight. So the bank vault and the gymnast's vault are distant cousins, both born from the idea of something curving through the air.