巧合
qiǎo hé · HSK 7
coincidence
巧 = opportune/coincidental + 合 = to fit together = a coincidence
巧 carries the sense of something happening just right or by chance, and 合 means to join or match up. Two things matching up by chance = a coincidence.
巧 — 工 (work) + 丂 (breath/exhalation phonetic)
巧 is a semantic-phonetic compound. The left 工 (work, craft) gives the meaning, pointing to skilled craftsmanship, while the right 丂 supplies the sound. From 'skilled handiwork' the meaning broadened to 'clever, ingenious,' and later to 'coincidental' as in 凑巧.
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.