- 四边形 sìbiānxíng quadrilaterala geometric shape in a single plane formed by four straight lines; examples include rectangles, parallelograms, and rhombuses
- 不规则四边形 bùguīzésìbiānxíng irregular quadrilateralirregular quadrilateral; trapezium
- 四边地 sìbiāndì scattered landScattered pieces of land situated on the edges of houses, roads, rivers, or hills
- 平行四边形 píngxíngsìbiānxíng parallelograma four-sided shape where the opposite sides are parallel and equal in length