HYPOSTYLE, in architecture, a term applied to halls with flat ceilings supported by columns, especially in Egyptian work. A hypostyle hall formed the largest room in every Egyptian temple. It was usually placed immediately behind the main court and in front of the small rooms that formed the sanctuary. Such halls were either lit by openings between the front range of columns, above the low screen wall built between them, as in the Ptolemaic temple at Edfu (237 to 57 B.c.) , or by having the central ranges of columns taller than those at the side so that a clerestorey of pierced stone screens was possible above the roof of the side por tions.