entries → 磋
TSUMUGU · C1 (est.) · 字
磋 character · C1 (est.)
磋 ＝ 石 ＋ 差
ㄘㄨㄛ · cuō
verb — to grind, polish (esp. bone or stone); to confer

字源 FORM — what the parts do

石義a stone
差聲chā — gives the soundto differ, be off (差)
IFTchā → cuō — reading reshaped off the donor
Working a stone (石) against another until it is smooth — to grind, to polish. 差 chā carries the sound, reshaped to cuō. The grinding became a figure for working a problem back and forth together: 切磋、磋商.

故事 STORY — a scene to remember it by

一塊石頭（石）來回磨著，磨到光滑——再難的事也磋出來了。
A stone (石) rubbed back and forth until it shines — and the hard matter is worked smooth too.
字源記憶法
意 · Meanings
(本義)切磋— to grind and polish (bone, stone)常用
→磋商— to confer — to work a matter back and forth
(本義) original meaning · → ⇒ each arrow = one more step of extension
關 · Related
差chāthe bare sound donor — 差 alone means "off, to differ"; 磋 adds the stone 石 (grind)蹉cuōthe 差 series — 蹉 takes the foot 足 (to stumble, 蹉跎), 磋 takes the stone 石