不约而同

bùyuēértóng · HSK 7

happen to coincide

🤝 not-arranged yet-same: no plan, same result

不 (not) + 约 (arrange/agree) + 而 (yet) + 同 (same). Nobody coordinated, yet everyone did the identical thing. Think of coworkers who all show up in the same color shirt without planning it.

不 — single pictograph; bird flying upward
Originally a pictograph in oracle bone script, traditionally interpreted as a bird flying up toward the sky and unable to come down, suggesting negation or refusal. Over time it became the standard negation word in Chinese, used before verbs and adjectives to mean 'not'.

约 — silk radical 糹/纟 + ladle 勺
约 combines the silk radical 糹 with 勺 (ladle), which provides the sound. Originally it referred to binding or tying with silk cords, from which came the meanings 'to bind by agreement,' hence 'pact, appointment,' and later 'approximately' (a loose, tied-up estimate).

而 — pictograph of beard/whiskers hanging from chin
Originally a pictograph of a beard or facial hair hanging below the chin, visible clearly in oracle bone and bronze script forms. The beard meaning was lost early, and the character was borrowed phonetically to write the grammatical conjunction 'and/but/yet'. This connective use has been standard since classical Chinese.

同 — 冂 enclosure + 一 + 口 mouth
Originally depicted multiple mouths gathered under one cover or enclosure, suggesting people speaking together in agreement. From this image of voices joining, it came to mean 'same,' 'together,' or 'alike.' The shared cover symbolizes unity.

More Chinese words · How Chinese works