The idiom **有朝一日** is formed through a classical Chinese poetic and metaphorical structure, where each of its four monosyllabic characters contributes to a unified, abstract meaning. Literally, **有** ("there is"), **朝** ("morning" or "day"), and **一日** ("one day") combine to mean "there is a morning, a day." However, its formation is not arithmetic but holistic, using the concrete image of a specific, yet indefinite, future day (**朝** and **一日** being synonymous reinforcements) introduced by **有** to create a fixed expression meaning "someday" or "one day in the future." This structure exemplifies a common pattern in Chinese idiom formation where tangible elements are layered to express an intangible, often aspirational or anticipatory, concept of time.