- 接地线 jiēdìxiàn ground wirea wire that connects an electrical circuit to the ground for safety, such as the lead on a lightning rod
- 测地线 cèdìxiàn geodesicthe shortest path between two points on a curved surface, such as a sphere
- 大地线 dàdìxiàn geodesicthe shortest path between two points on a curved surface; a geodesic curve
- 测地线曲率 cèdìxiànqūlǜ geodesic curvature
