TSUMUGU · A2 · 字
旬
旬 ＝ 勹 ＋ 日
ㄒㄩㄣˊ · xún
noun — a ten-day period; a span of ten
字源 FORM — what the parts do
勹義a wrapping arm, closing round
An arm (勹) wraps around the sun (日) — ten days gathered into one closed round. That bundle is a 旬: 上旬、中旬、下旬.
故事 STORY — a scene to remember it by
手臂（勹）一彎，把十個太陽（日）圈進懷裡——一旬。
The arm (勹) curls and gathers ten suns (日) into its hold — one xún.
字源記憶法
意 · Meanings
(本義)十日— a span of ten days常用
→上旬、中旬— the early / middle third of a month
⇒旬日— ten days' time
(本義) original meaning · → ⇒ each arrow = one more step of extension