entries → 壇
TSUMUGU · C1 (est.) · 字
壇 character · C1 (est.)
壇 ＝ 土 ＋ 亶
ㄊㄢˊ · tán
noun — a raised altar; a platform, arena

字源 FORM — what the parts do

土義earth raised into a platform
亶聲dǎn — gives the sounda granary 㐭 over 旦 — stored full, generous
{d,t}ITdǎn → tán — the {d,t} crossing; tone shifts too
Earth (土) banked up into a flat raised stage; 亶 dǎn carries the sound, d worn to t. A platform for rites, then for speaking and for a whole field: 祭壇、講壇、文壇、論壇.

故事 STORY — a scene to remember it by

一層層土（土）夯成平臺，人站上去主祭——一座壇。
Earth (土) tamped into a flat stage; he steps up to lead the rite — an altar.
字源記憶法
意 · Meanings
(本義)祭壇— an altar常用
→講壇、論壇— a platform, rostrum
⇒文壇、影壇— a field, arena (literary, film)
(本義) original meaning · → ⇒ each arrow = one more step of extension
關 · Related
檀tánshares 亶 — 檀 takes the tree 木, 壇 takes the earth 土亶dǎnthe sound half — 壇 adds 土, 亶 alone is the full granary