The ambulatory (Med. Lat. ambulatorium, a place for walking, from ambulare, to walk) is the covered passage round a cloister; a term applied sometimes to the procession way round the east end of a cathedral or large church and behind the high altar. Cloister of Saint Trophimus, in Arles, France A cloister (from latin claustrum) is part of cathedrals and abbeys architecture. ... A cathedral is a Christian church building, specifically of a denomination with an episcopal hierarchy (such as the Roman Catholic Church or the Anglican churches), which serves as the central church of a bishopric. ... Picture of an altar from the Meyer Encyclopaedia An altar, (Hebrew mizbeah, from a word meaning to slay) is any structure on which sacrifices known as the korbanot as well as incense offerings are offered for religious purposes. ...
An ambulatory without radiating chapels is so rare in Romanesque work that supposed examples should be regarded as doubtful.
Sometimes there is a rectangular ambulatory, as in the Romsey eastern chapel.
Ambulatories are constructed either on the inside or outside of a building, or in a public thoroughfare wholly or partially under cover, or entirely open to the sky, and are used only to walk in.