An underground vault is a secure room or space located below the ground level. It is typically used to store valuable items or sensitive information, providing additional protection and privacy due to its hidden location. Full definition
Under orders of India's Supreme Court, officials since last week have been auditing precious royal offerings kept in underground vaults of the famed Sree Padmnabha Swamy temple in the coastal state of Kerala. (religion.blogs.cnn.com)
Piano designed a «centripetal» building, partially buried underground in order to cope with the tight space available for the expansion and «to build a sort of underground vault in which to house the library's rare book collection. (inexhibit.com)
An investigation by the Illinois Environmental Protection Agency showed that the samples were drawn from underground vaults with lead piping instead of home and business sites. (articles.chicagotribune.com)