Semiarched

Semiarched is an adjective used in architecture and design to describe an element that incorporates an arch-like curve but does not form a complete arch. In practice, semiarched features exhibit a curvature that covers only part of an opening, facade, or profile. The term can apply to windows and doorways with a partial semicircular or segmental curve that is shallower than a full arch, to moldings that terminate before completing an arch, or to decorative elements that imitate an arch without meeting at a keystone.

Etymology and scope: Derived from semi- meaning half and arch, the term signals partial curvature rather than a structurally self-supporting arch. It is more commonly found in descriptive writing and design discussions than in formal construction terminology.

Applications: In architecture, semiarches can soften interfaces between rectangular volumes, mark transitions between spaces, or provide visual interest in façades where a full arch would be impractical. In restoration work, identifying semiarched features helps distinguish original fabric from later modifications.

Relation to other forms: A true arch is a curved opening that transfers load through a keystone; a semiarch is a partial version whose effectiveness often depends on surrounding framing. Related concepts include segmental, elliptical, and lancet arches, which vary in curvature and extent but retain a defined arching profile.

See also: arch, segmental arch, elliptical arch, lancet arch, architrave.