The word 预定 is formed by combining two meaningful characters: 预, which carries the idea of "beforehand" or "in advance", and 定, which means "to fix", "to settle", or "to decide". Conceptually, the first character establishes the temporal framework (doing something ahead of time), and the second character specifies the core action (making something firm or decided). Their combination logically and seamlessly creates the single concept of "to pre-determine" or "to reserve", where an arrangement is settled or fixed prior to the expected time of the event or need.