noun
convex polygon
Technical term in geometry; all interior angles are less than 180 degrees.
See also: 凹多角形
正五角形は凸多角形の一種です。
A regular pentagon is a type of convex polygon.
Concave polygon; at least one interior angle is greater than 180 degrees.
Compound of 凸 (convex) + 多角形 (polygon).