还原
huán yuán · HSK 7
to restore to the original state
还 (return) + 原 (original) = return something to its original state
还 means to give back or return; 原 means origin or original. Together: bring a thing back to how it first was — undo changes, rebuild an event, or in chemistry, reduce a compound.
还 — 辶 (walk) + 不 (not) — phonetic
还 is the simplified form of 還. The traditional form combines the walking radical 辶 with 睘 (a phonetic element originally depicting an eye over a ring), suggesting 'to go around and return.' The simplified 还 keeps 辶 and replaces 睘 with 不 as a simpler phonetic. Core meaning: return, still, also.
原 — cliff 厂 + spring 泉 (white 白 + water 水)
Originally a pictograph showing a spring of water flowing out from beneath a cliff, depicting the source of a stream. From this concrete image of a water source, the meaning extended to 'origin,' 'source,' and 'original.' A separate character 源 was later created with the water radical 氵 to keep the literal 'spring' sense.