An opening or frame, which may be either load-bearing or decorative, with a profile based on the segment of a circle or series of segments. A true brick or masonry arch is a composite structure, whose wedge-shaped constructional blocks (voussoirs) are disposed radially and held together in compression. A series of arches springing from columns or piers or cut through a wall is known as an arcade, and is often used around courtyards in Islamic architecture. A blind arch refers to an arch which is filled in; blind arches are frequently used for decoration on the external walls of buildings, like those on the Gunbad-i Surkh (1147–8) at Maragha in Iran.
The arch, like many of the architectural forms used in the design of early mosques in the Mediterranean region (see Mosque), was adapted from the local Roman architecture. From the outset, however, Islamic designers were far more adventurous than their Roman forebears. A semi-circular arch springing from columns appears in some Umayyad architecture, such as the entrance of the prayer-hall of the Great Mosque of Damascus (706–15; ...