Semicircular arch
Arch shape common in ancient Roman architecture / From Wikipedia, the free encyclopedia
"Roman arch" redirects here. For the triumphal arches built in Rome, see Roman triumphal arch. For the concept in general relativity, see Roman arch (physics). For the racehorse, see Roman Arch.
In architecture, a semicircular arch is an arch with an intrados (inner surface) shaped like a semicircle.[1][2] This type of arch was adopted and very widely used by the Romans, thus becoming permanently associated with Roman architecture.[3]
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Round_arches.png/320px-Round_arches.png)