The ambulatory is the covered passage around a cloister
A cloister is a rectangular open space surrounded by covered walks or open galleries, with open arcades on the inner side, running along the walls of buildings and forming a quadrangle or garth...
. The term is sometimes applied to the procession way around the east end of a cathedral
A cathedral is a Christian church that contains the seat of a bishop...
or large church and behind the high altar
An altar is any structure upon which offerings such as sacrifices are made for religious purposes. Altars are usually found at shrines, and they can be located in temples, churches and other places of worship...