旬

Also “decade” (in the sense of 10 days, not years); also extended to mean a cycle of ten, sometimes a decade of years.

Originally an ideograph / pictograph in oracle bone script:

Early forms show 十 (“ten”) combined with a coiled or looping shape resembling a curled worm or serpent.

Interpreted variously as representing a worm (本字 of 螾 “earthworm”), a snake, or a dragon.

Another interpretation: the coiled form symbolizes a cycle or loop that repeats every ten days.

Later developments:

In bronze inscriptions, 日 (“sun, day”) was added to emphasize the time aspect.

By the seal script stage, the coiled form evolved into 勹-like shape, producing the modern form 旬.

Semantic range:

- a ten-day period (used in calendars of ancient China);

- by extension, a cycle, a span of time;

- sometimes used for “ten years” in literary or poetic contexts;

- in compounds, denotes “a period” or “time span.”

상순 (上旬) – the first ten days of a month

중순 (中旬) – the middle ten days of a month

하순 (下旬) – the last ten days of a month

순일 (旬日) – ten days’ time

Though 旬 can mean “ten years” in certain texts, the primary and standard meaning is the ten-day period used in traditional calendrical reckoning.

Closely tied to the ancient Chinese calendrical system, where months were divided into three 旬 (上旬, 中旬, 下旬).