A cubiculum, from the Latin verb cubare meaning “to lie, to rest”, was a burial chamber in the catacombs.
This term was exclusively Christian; pagans used it to refer to secondary bedrooms, children’s or guest bedrooms.
The shape of this space varied: it could be circular, semi-circular, square, triangular or hexagonal. Sometimes this room received light from an open circular hole in its vault, but it was partly immersed in darkness.
The cubicula were generally not family tombs, but rather appeared as chapels ending in an apse, where there was the tomb of a martyr in an arcosolium, an arch-shaped burial structure surmounted by a niche and carved into the wall.