In architecture, a quadrangle is a space or a courtyard, usually rectangular in plan, the sides of which are entirely or mainly occupied by parts of a large building. The word is probably most closely associated with college or university campus architecture, but quadrangles are also found in other buildings such as palaces. Most quadrangles are open-air, though a few have been roofed over, to provide additional space for social meeting areas or coffee shops for students.

A cloister is a covered walk, open gallery, or open arcade running along the walls of buildings and forming a quadrangle or garth. The attachment of a cloister to a cathedral or church, commonly against a warm southern flank, usually indicates that it is part of a monastic foundation, "forming a continuous and solid architectural barrier... that effectively separates the world of the monks from that of the serfs and workmen, whose lives and works went forward outside and around the cloister."