出发 (chū fā) is a verb meaning 'to set off' or 'to depart' — it describes the action of beginning a journey from a starting point. The character 出 means 'to go out' or 'to emerge', and 发 means 'to send off' or 'to initiate'; together, they convey the idea of initiating movement away from a place. It’s commonly used for planned departures — whether by foot, car, train, plane, or other transport — and often appears with time expressions (e.g., 早上八点出发) or destinations (e.g., 去北京出发).

This word carries a neutral-to-formal register and is widely used in daily speech, travel announcements, schedules, and written instructions. Unlike the more casual 走 (zǒu) or the physical-action-focused 离开 (lí kāi), 出发 emphasizes the intentional start of a trip or mission, often implying preparation and purpose. It’s frequently paired with directional complements like 出发去… (chū fā qù…) or 出发到… (chū fā dào…), and can be modified by adverbs like 马上 (mǎ shàng, 'immediately') or 明天 (míng tiān, 'tomorrow').