[un.der.croft] n [ME, fr. under + crofte crypt, fr. MD, fr. ML crupta, fr. L crypta--more at crypt] (14c): a subterranean room; esp: a vaulted chamber under a church
UNDERCROFT
Meaning of UNDERCROFT in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012