- 平行线 píngxíngxiàn parallel lines
- 平行六面体 píngxíngliùmiàntǐ parallelepiped(math.) parallelepiped
- 平行时空 píngxíngshíkōng parallel universe
- 平行计算 píngxíngjìsuàn parallel computing
- 平行四边形 píngxíngsìbiānxíng parallelogram
- 平行公设 píngxínggōngshè parallel postulateThe fifth postulate of Euclidean geometry, which states that exactly one line can be drawn through a given point parallel to a given line.