a reinforced outer structure that protects the casket against moisture and the weight of the earth
a structure that is placed underground to hold the casket
A boxlike container for holding a casket for earth burial; the more substantial vault or a liner is required by most cemeteries to prevent the collapse of a grave after burial.
A burial vault is a sturdy box designed to protect the coffin inside of it. The body is placed within the coffin, which is then placed inside the vault. Body, coffin, and vault are buried.
A burial vault is a structural underground tomb.