crypt | architecture | Britannica
crypt, vault or subterranean chamber, usually under a church floor. In Latin, crypta designated any vaulted building partially or entirely below the ground level, such as sewers, the stalls for horses and chariots in a circus, farm storage cellars, or a long gallery known as a cryptoporticus, like that on the Palatine Hill in Rome. It was natural, therefore, for the early Christians to call their catacombs crypts; and, when churches came to be erected over the tombs of saints and martyrs, subterranean chapels, known as crypts or confessiones, were built around the actual tomb. The most famous of these