vaults
n. plural-onlyn. strong rooms or safe places, usually underground, used to keep money or valuable things safe. They are often found in banks or old buildings.
n. secure rooms or compartments, typically constructed of steel or masonry, designed for the safekeeping of valuables. Often refers to subterranean chambers or the arched structures of a cellar.
The bank keeps its gold bars in underground vaults.
The museum stores its most fragile artifacts in climate-controlled vaults to prevent any environmental damage.
Deep beneath the city streets, the ancient cathedral's vaults contain the remains of several historical figures and a collection of medieval manuscripts.
Often used in the plural when referring to a series of underground rooms or a general storage area.