由

In oracle bone script, it depicted a mouth (口) with a drop or mark above it, possibly symbolizing something emerging or coming from.

Later stabilized into the modern form 由.

Used independently in a limited sense (reason, cause, path).

Very frequently serves as a phonetic component in other characters, e.g.:

油 (oil);

柚 (citron, pomelo tree);

釉 (glaze, enamel).

이유 (理由) – reason, cause

자유 (自由) – freedom

유래 (由來) – origin

In some contexts it carries the archaic meaning “a woman’s smiling expression”, in which case it is read 요.