终于
zhōngyū · HSK 3
at last
⏳ 终 = end + 于 = at; 'at the end' → finally, at last
终 means end/final (silk radical 糸 + winter 冬, originally tying off a thread). 于 is a classical preposition meaning 'at/in'. Together: 'at the end' = at last, finally.
于 — two horizontal strokes 二 + vertical hook 亅
于 originated as a pictograph of breath or sound flowing outward, depicting exhalation through a passage. In oracle bone script it resembled a curved line showing motion or extension. Over time it became a grammatical preposition meaning 'at,' 'in,' or 'to,' losing its original concrete sense.