Wiktionary
hemicylindrical
a. Having the form of half a cylinder (divided down its axis)
Usage examples of "hemicylindrical".
It turned out to be hinged under a hemicylindrical sleeve, folding as it carried back, and as it reached maximum fold, a cartridge flew out of the chamber and clattered on the closet floor.
Sitting with his back against a dormer and his booted feet braced on the red hemicylindrical roofing tiles, Stillhawk furrowed his brow, his equivalent of an angry outburst.
They passed through to find themselves in a hemicylindrical chamber of glazed green brick, fifty yards long and maybe seven high.