冲洗
chōng xǐ · HSK 7
to wash
🚿 chōng xǐ = rush/pour + wash — water rushing over something to rinse it clean
冲 means to rush or flush (water pouring forcefully), 洗 means to wash. Together: a forceful rinse. The film-developing sense comes from the chemical wash process in a darkroom.
冲 — water radical 氵 + middle 中
Originally written 沖, combining the water radical 氵 with 中 ('middle') as the phonetic. The early sense was water surging or pouring, which extended to 'rush, charge, clash.' In simplified Chinese it merged with 冲 (ice radical 冫 + 中), so today 冲 covers both the 'rinse/rush' meanings and some older 沖 uses.
洗 — water radical 氵 + 先 (xiān)
A semantic-phonetic compound. The water radical 氵 indicates the meaning (washing with water), while 先 supplies the sound, originally close to xiǎn/xǐ. The character has long meant 'to wash' or 'rinse,' and by extension 'to cleanse' or 'wash away.'