昔

A marker of temporal distance denoting the past as viewed from the present. It functions adverbially ("formerly," "once," "long ago") to establish a narrative baseline or contrast, and substantively ("antiquity," "the old days"), often with an evaluative or nostalgic tone. The sense of "in beginning" refers specifically to the primordial past (the dawn of time) rather than the inception of a specific event.

Often appears as a temporal marker at the beginning of a phrase or clause to signal a shift in perspective. It can also serve as a modifier for nouns related to time, such as 日.

Unlike 古 (gǔ), which typically refers to antiquity as an objective quality, fixed epoch, or standard, 昔 is more retrospective and subjective. Unlike 舊 (jiù), which denotes physical age, wear, or obsolescence, 昔 is strictly chronological/temporal.