于

Originally pictographic / loan character.

In oracle bone script, 于 originally represented "possibly a bent object or tool."

Some scholars connect it to movement or extension. However, its original concrete meaning was lost, and it became widely used as a phonetic loan for grammatical functions.

By the Zhou dynasty, 于 was used mainly as "a preposition-like particle."

Used mainly in literary Sino-Korean compounds:

급우 (及友) — classmate (older usage)

우연 (偶然) — coincidence (not same 于 but same pronunciation)

于 is one of the foundational particles of Classical Chinese grammar.

It functions similarly to English “in / at / to / from / than.”

Because Classical Chinese is highly compact, 于 carried multiple relational meanings.

Unlike semantic characters, 于:

- does not represent a concrete object

- represents grammatical relationship

It is a structural character — essential for understanding classical texts.

It functions similarly to the character 於, serving as a preposition or particle in classical Chinese.

In usage, 于 and 於 are often interchangeable, both expressing relations such as "in," "at," "to," "from," or "than", depending on context.

Though it has other historical uses, 于 is now mainly seen in literary or formal language, especially in classical texts or set phrases.

Examples:

生于忧患 — “Born in hardship”

于心不忍 — “Cannot bear it in one’s heart”

终于成功 — “Finally succeed”