Kryptae
From BiblePortal Wikipedia
Kryptae [1]
( Κρύπται , Crypts). For the purpose of concealment from their persecutors, the early Christians occasionally prepared for themselves churches and oratories under ground, which served both as places of' devotion and as sepulchres for their dead. These were called Cryptce, from Κρύπτω , to conceal.-Farrar, Eccles. Dict. (See Crypt).