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1. A structure based on the principle of the arch, often constructed of masonry; typically consists of an arrangement of arches that cover the space below; also see barrel vault, cradle vault, cylindrical vault, fan vault, groined vault, lierne vault, rampant vault, ribbed vault, segmental vault, sidewalk vault, stilted vault, tunnel vault, wagon vault, Welsh vault.
2. A burial chamber, especially one under a church.
3. An underground chamber especially designed for maintaining electrical equipment.
4. A room for the safekeeping of valuables.