The etymology of the Latin word catacumba is uncertain. It is thought to derive from the Greek locution katá kymbḗs: “near the caves.”
These underground cemetery areas were usually excavated in the tuff and could be even thirty meters deep.
The most famous catacombs were the Christian ones: the Christians embraced the inhumative practice and abandoned, by faith in the resurrection of bodies, the use of pagan cremation.
The ancient term to designate these monuments is coemeterium, which  derives from the Greek and means “dormitory”, underlining that for Christians the burial is a temporary moment, waiting for the resurrection.