合理
hélǐ · HSK 3
reasonable
⚖️ 合 = combine + 理 = reason/logic → fits with reason = reasonable
合 means to join or fit together; 理 means reason, logic, or principle. Something 合理 literally fits with reason — it lines up with logic, so it's plausible, rational, or legitimate.
合 — 乛 (lid/roof) + 口 (mouth)
Originally a pictograph of a lidded vessel — a cover (亼) closing over an opening (口) — giving the core sense of 'come together, join, fit.' From 'fit/match' it extended to 'combine, unite, agree' and to measure-word uses. The reading hé reflects this 'joining' meaning.
理 — jade radical 玉/王 + village 里 (phonetic)
理 is a semantic-phonetic compound: the jade radical 王 (玉) on the left signals meaning, while 里 on the right gives the sound. It originally meant the natural veins or grain in a piece of jade, then extended to 'pattern,' 'order,' 'principle,' and finally the modern senses 'reason' and 'to manage.'