A lapis manalis was either of two sacred stones used in the Roman religion. One covered a gate to Hades, abode of the dead; Sextus Pompeius Festus called it ostium Orci, "the gate of Orcus". The other was used to make rain; this one may have no direct relationship with the Manes, but is instead derived from the verb manare, "to flow".
The two stones had the same name. However, the grammarian Festus held the cover to the gate of the underworld and the rainmaking stone to be two distinct stones.[1]
- ^ Sextus Pompeius Festus, De verborum significatione, sub. tit. manalis (Latin and French text)