undercroft Meaning, Definition & Usage

Un"der*croft noun
Etymology
Under + Prov. E. croft a vault; cf. OD. krochte crypt, and E. crypt.
Definitions
  1. (Arch.) A subterranean room of any kind; esp., one under a church (see Crypt), or one used as a chapel or for any sacred purpose.

Webster 1913