合乎
héhū · HSK 7
conform with/to
🧩 合 fit/join + 乎 classical particle to; 合乎 = fit-to, conform to
合 means to join or match, and 乎 is an old written particle meaning to or with. Stuck together they read as fit-to: to tally with or accord with a standard or rule.
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.