a burial chamber (usually underground)
"The ancient king was interred in an ornate stone vault beneath the cathedral floor."
a strongroom or compartment (often made of steel) for safekeeping of valuables
"The bank manager carefully locked the stolen diamonds into the reinforced vault before leaving for the day."
an arched brick or stone ceiling or roof
"The ancient cathedral features a magnificent vault made of intricate stone ribs that draws the eye upward."
An arched masonry structure supporting and forming a ceiling, whether freestanding or forming part of a larger building.
"The stag executed a graceful vault over the fallen log before bounding into the dense forest."
An act of vaulting, formerly (chiefly) by deer; a leap or jump.
In plain English: A vault is a secure room with strong walls and doors used to keep valuable things safe from theft.
"The gymnast performed an impressive vault across the floor exercise mat before landing on her feet."
Usage: Use "vault" to refer specifically to an arched ceiling structure made of stone or brick that supports the roof above it. This architectural term distinguishes such spaces from flat ceilings or domes found in other building designs.
To build as, or cover with a vault.
"The gymnast executed a perfect vault by leaping high and clearing the uneven bars without touching them."
To jump or leap over.
In plain English: To vault means to jump over something by pushing off with your legs and using your hands for balance if needed.
"The gymnast vaulted over the high bar with great skill."
The word vault comes from Old French volte, which originally meant "arch" or "ceiling." It entered English via Middle English after describing the curved structure formed by rolling stone blocks together, derived ultimately from a Latin root meaning to roll or turn.