The word 预告 is formed by combining two meaningful characters: 预 (yù), which carries the core idea of "in advance" or "beforehand", and 告 (gào), which means "to tell" or "to notify". Their union is conceptual, creating a composite idea where the sense of 告 is placed within the temporal framework of 预, thus directly conveying the meaning of "to notify beforehand" or "an advance notice".