‘航线’ (háng xiàn) literally combines ‘航’ (háng), meaning ‘to sail’ or ‘to fly’, and ‘线’ (xiàn), meaning ‘line’ or ‘route’. Together, it refers to a designated path or corridor used for transportation—most commonly for aircraft or ships. It implies an officially planned, regularly operated, and often regulated route between two or more points.

This term is widely used in aviation and maritime contexts: airlines publish their flight routes as ‘航线’, while shipping companies refer to sea passages—such as those across the South China Sea—as ‘航线’. It can also appear in logistics, tourism, and government transport planning. Unlike casual terms like ‘路线’ (lù xiàn, general route), ‘航线’ carries a formal, technical connotation and almost always refers to long-distance, scheduled, or commercial transport corridors.