A trefoil arch, or three-foiled cusped arch (occasionally trilobite arch, no connection to an actual trilobite), is an arch incorporating the shape or outline of a trefoil – three overlapping circles.[1] It has been widely used for its symbolic significance in Christian architecture.[citation needed] Trefoil arches are common in Gothic architecture for portals and decoration.[1] Trefoil or "trilobed" arches are also a characteristic feature of decorated portals in late Fatimid architecture and Mamluk architecture in Egypt, from approximately the 12th to 16th centuries.[2]: 191 [3]: 89
^Behrens-Abouseif, Doris (2007). Cairo of the Mamluks: A History of Architecture and its Culture. The American University in Cairo Press. ISBN9789774160776.