noun
regular polygon
A polygon with all sides and angles equal. Used in geometry and mathematics.
正多角形の内角の和を求める公式を覚えていますか。
Do you remember the formula for finding the sum of the interior angles of a regular polygon?
多角形 is a general polygon, while 正多角形 specifically means a regular polygon with equal sides and angles.
Compound of 正 (regular, correct) and 多角形 (polygon). The term is a direct calque from Western mathematical terminology.