閏

Primarily used in the context of the lunisolar calendar to denote an inserted month (閏月) or day (閏日) necessary to synchronize the lunar year with the solar year. In extended or metaphorical use, it denotes a surplus or addition used to fill a gap.

Contrast with 餘 (yú): while 餘 typically refers to a remainder, leftover, or residue, 閏 implies a corrective addition—a surplus intended to achieve alignment or synchronization.

Simplified variant: 闰 (U+95F0). Tang-period reading: njuìn.

When encountered outside of a strict calendar date, consider if the term is being used as a metaphor for "correcting a discrepancy" or "filling a void." In philosophical or poetic contexts, the technical sense of "intercalary" may shift toward "inserted extra" or "corrective surplus."