预订 means 'to reserve (in advance)' — a verb used when securing something ahead of time, such as a hotel room, restaurant table, flight, or ticket. The character 预 means 'in advance' or 'pre-', and 订 means 'to order' or 'to arrange'; together, they convey the idea of arranging something ahead of its use or arrival. This word emphasizes intentionality and planning, distinguishing it from spontaneous actions.

It’s commonly used in travel, hospitality, and service contexts, especially where availability is limited or demand is high. 预订 is neutral in register — appropriate in both spoken and written Chinese, from casual online bookings to formal business communications. Unlike the more general 订 (to order), 预订 always implies advance timing; you wouldn’t use it for something happening immediately. It often appears with time markers like 明天 (tomorrow), 下周 (next week), or 提前 (in advance) to reinforce that temporal element.