TSUMUGU · C1 (est.) · 字
于
ㄩˊ · yú
prep — in, at, to, from (a preposition)
字源 FORM — what the parts do
于形two strokes turned by a hook
A grammatical word through and through: the joint that fixes a verb to its place, time, or target — 生于、勇于、出于. It marks where, when, toward what.
意 · Meanings
(本義)在、到、向— in; at; to (a preposition)常用
→出于、由于— out of; owing to
⇒于（姓）— a surname
(本義) original meaning · → ⇒ each arrow = one more step of extension