- an underground cemetery, especially one consisting of tunnels and rooms with recesses dug out for coffins and tombs.
- the subterranean burial chambers of the early Christians in and near Rome, Italy.
- an underground passageway, especially one full of twists and turns.
- an underground burial place, esp the galleries at Rome, consisting of tunnels with vaults or niches leading off them for tombs
- a series of interconnected underground tunnels or caves
