A sahn (Arabic: صَحْن, ṣaḥn), is a courtyard in Islamic architecture, especially the formal courtyard of a mosque. Most traditional mosques have a large central sahn, which is surrounded by a riwaq or arcade on all sides. In traditional Islamic design, residences and neighborhoods can have private sahn courtyards. The sahn is a common element in religious buildings and residences throughout the Muslim world, used in urban and rural settings. The cloister is its equivalent in European medieval architecture and its religious buildings.