A (left or right) half-segment of an arch is called an arc, the overall line of an arch is arcature[18] (this term is also used for an arcade).[19] Archivolt is the exposed (front-facing) part of the arch, sometimes decorated (occasionally also used to designate the intrados).[20] If the sides of voussoir blocks are not straight, but include angles and curves for interlocking, the arch is called "joggled".[21]