TSUMUGU · TOCFL 3 (est.) · 字
億
億 ＝ 亻 ＋ 意
ㄧˋ · yì
num — a hundred million
字源 FORM — what the parts do
亻義a person
A person (亻) with 意 yì for the sound, an exact match. The old sense is a mind at ease; the number took the graph over — 萬萬, ten thousand ten-thousands, the hundred million of 億元.
意 · Meanings
(本義)安（古義，已不用）— at ease — the old sense, gone from use
→億、億萬— a hundred million常用
(本義) original meaning · → ⇒ each arrow = one more step of extension