Iwan (noun) An iwan is a vaulted room open on one side, usually onto a courtyard in an Islamic mosque. The iwan in Omar Khayyam’s tomb in Neishabour, Iran is decorated with characteristic Islamic geometric and vegetal motifs.
Vault and colored ceiling of the Iwan of an Imamzadeh at the tomb of Omar Khayyam, 1962, Photo by By dynamosquito via Flickr, Creative Commons Attribution-Share Alike 2.0 Generic license.