vault

An arched masonry structure supporting and forming a ceiling, whether freestanding or forming part of a larger building.

Any arched ceiling or roof.

Anything resembling such a downward-facing concave structure, particularly the sky and caves.

The space covered by an arched roof, particularly underground rooms and (Christianity, obsolete) church crypts.

Any cellar or underground storeroom.

Any burial chamber, particularly those underground.

The secure room or rooms in or below a bank used to store currency and other valuables; similar rooms in other settings.

Any archive of past content.

An encrypted digital archive.

An underground or covered conduit for water or waste; a drain; a sewer.