Vault > define

(n.) To exhibit feats of tumbling or leaping; to tumble.
(n.) To leap; to bound; to jump; to spring.
(v.i.) To leap over; especially, to leap over by aid of the hands or a pole; as, to vault a fence.
(n.) An arched structure of masonry, forming a ceiling or canopy.
(n.) A leap by aid of the hands or of a pole, springboard or the like.
(n.) An arched apartment; especially, a subterranean room, use for storing articles, for a prison, for interment or the like; a cell; a cellar.
(v.t.) To form with a vault or to cover with a vault; to give the shape of an arch to; to arch; as, vault a roof; to vault a passage to a court.
(n.) The canopy of heaven; the sky.
(n.) The bound or leap of a horse; a curvet.
(n.) A leap or bound.

by Webster's Revised Unabridged Dictionary

A burial chamber (usually underground.
- synonyms: burial vault
A strongroom or compartment (often made of steel) for safekeeping of valuables.
- synonyms: bank vault
An arched brick or stone ceiling or roof.
The act of jumping over an obstacle.
- synonyms: hurdle

vault is a secure room or rooms in a financial institution where cash on hand is stored and safe deposit boxes are located.