[aiwan, eyvan, ivan, liwan; Pers. ayvān, Arab. īwān]
Vaulted hall with walls on three sides and completely open on the fourth. In classical Persian and Arabic texts the term usually refers to a palace building or some formal part of a palace, such as a platform, balcony or portico; only among modern archaeologists and art historians is the word applied solely to this type of vaulted hall. The basic form of the iwan can be traced back to Mesopotamia and Iran during the time of the Parthians (see Parthian) and Sasanians (c. 250 bc–ad 651), but its full architectural potential was realized by Islamic builders from Egypt to India, who made it a distinctive feature of their secular and religious monuments.
The origin and early development of the iwan are the subject of debate, and no convincing solution to these problems will be possible until more archaeological data is available from Iran and Central Asia, where the iwan became such an important architectural feature. Some large halls at ...