semiround

sem·i·round

S0258000 (sĕm′ē-round′, sĕm′ī-)adj. Having a round side and a flat side.

semiround

(ˌsɛmɪˈraʊnd) n (Mathematics) a semiround object or shapeadj (Mathematics) with one flat side and one round side; having the shape of half a circle; semicircular