TSUMUGU · B2 (est.) · 字
兌
ㄉㄨㄟˋ · duì
verb — to exchange, convert (currency); to cash
字源 FORM — what the parts do
The old graph carries two tellings. In one, a person (儿) opens the mouth (口) and breath parts upward (八) — speech, and the gladness of it; this is the root the trigram 兌 keeps, lake and joy. In the other, 八 is the divide-mark — to split a thing in two and hand half across. Both feed the everyday sense: 兌換, to swap one currency for another; 兌現, to make good, to cash.
故事 STORY — a scene to remember it by
兩手把一錠銀分開（八），一半遞過去——換成你要的。
Two hands part a piece of silver (八), pass half across — swapped for what you came for.
字源記憶法
意 · Meanings
(本義)兌換、兌現— to exchange, to cash常用
→兌 (卦名)— the trigram 兌 — lake, joy
(本義) original meaning · → ⇒ each arrow = one more step of extension