Real Dictionary

cloister
countable noun: A cloister is a covered area round a square in a monastery or a cathedral.

cloister in American English
a place of religious seclusion: monastery or convent
to seclude or confine in or as in a cloister
noun: a covered walk, esp. in a religious institution, having an open arcade or colonnade usually opening onto a courtyard
transitive verb: to confine in a monastery or convent

cloister in British English
noun: a covered walk, usually around a quadrangle in a religious institution, having an open arcade or colonnade on the inside and a wall on the outside
verb: to confine or seclude in or as if in a monastery