Real Dictionary

crypt
countable noun: A crypt is an underground room underneath a church or cathedral.

crypt in American English
an underground chamber or vault, as one under the main floor of a church, often, esp. formerly, serving as a burial place
noun: a subterranean chamber or vault, esp. one beneath the main floor of a church, used as a burial place, a location for secret meetings, etc

crypt in British English
noun: a cellar, vault, or underground chamber, esp beneath a church, where it is often used as a chapel, burial place, etc

crypt- in American English
crypto-