- 北回归线 Běihuíguīxiàn Tropic of Cancerthe Tropic of Cancer
- 南回归线 Nánhuíguīxiàn Tropic of Capricorn
- 回归线 huíguīxiàn tropicone of the two latitude lines, the Tropic of Capricorn or the Tropic of Cancer, marking the boundaries of the tropical zone
- 回归年 huíguīnián solar yearthe year defined as the period between successive equinoxes
- 回归热 huíguīrè relapsing feverrecurring fever
- 线性回归 xiànxìnghuíguī linear regressionlinear regression (statistics)