Complex sentence: The ambulatory (Medieval Latin "ambulatorium", a place for walking, from "ambulare", to walk) is the covered passage around a cloister, or the processional way around the east end of a cathedral or large church and behind the high altar.
Split into simpler sentences: The ambulatory (Medieval Latin "ambulatorium", a place for walking, from "ambulare", to walk) is the covered passage around a cloister. The term is sometimes applied to the processional way around the east end of a cathedral or large church and behind the high altar.