The word "semicircle" is correct and can be used in written English.
You can use it to describe a shape that is half a circle. For example, "The moon appears to create a perfect semicircle in the night sky."
It was left to the energetic, cheerful Mr Gillies to call this archipelago of thousand-foot peaks, cliffs and bird-crammed stacs his "little homeland", and to call Cottage No. 10, in the semicircle of 16 tiny houses on the only street on Hirta, the main island, his home.
Cities are not circular: Hull is a rough semicircle.
Pistoia city lies in the valley of the Ombrone River, with a semicircle of pleasant hills (part of the Apennines) to the north.
In the shape of a semicircle, this is fastened around the perimeter of the craft; the lower edge is taken inward and upward and is fastened inboard, below the hull.
A semicircle has its end points on a diameter of a circle.
It lies between a well-sheltered, deepwater harbour, accessible to ships through a break in the coral reef, and a semicircle of mountains.
For example, to cut a beveled edge on a table, or a V groove, a silhouette of the rotating cutter would have a V shape; to cut a semicircular groove the silhouette would be a semicircle with the diameter perpendicular to the shank; to cut a beaded (rounded) edge on a table the silhouette would be a rectangle with quarter circles cut from the lower corners.
The mirrors are placed in concentric semicircles facing a tower, on top of which the boiler and the turbine sit.
During flight the wings form broad semicircles on each side between the limbs.
Pest's main boulevards form concentric semicircles around the Belváros.
As depicted in the cyclonic circulation stage (C), the front that signals the advancing cold air (cold front) is indicated by the triangles, while the front corresponding to the advancing warm air (warm front) is indicated by the semicircles.
