- 不规则性 bùguīzéxìng irregularitythe state or quality of being irregular; lack of uniformity or regularity
- 不规则三角形 bùguīzésānjiǎoxíng scalene trianglea triangle in which all three sides have different lengths; scalene triangle
- 不规则四边形 bùguīzésìbiānxíng irregular quadrilateralirregular quadrilateral; trapezium