众志成城
zhòng zhì chéng chéng · HSK 7
unity of will is an impregnable stronghold (idiom)
👥🧱 众 many + 志 will + 成 become + 城 city wall: many wills become a fortress
Four characters stack literally: a crowd's shared resolve hardens into a city wall no enemy can break. Used when a group's unity makes them as solid as fortifications.
成 — 戊 (halberd/weapon) + 丁 (nail/man)
Originally a pictograph of a halberd or axe-like weapon, suggesting the act of completing a task by force. Over time it shifted from 'to subdue' to the broader meaning 'to accomplish' or 'to become'. The 丁 element inside also hints at the chéng sound.
城 — earth radical 土 + 成 (to complete)
Originally a semantic-phonetic compound: 土 (earth) gives the meaning, since ancient cities were defended by rammed-earth walls, while 成 supplies the sound. The earliest meaning was 'city wall,' which later broadened to 'walled city' and then simply 'city' or 'town.'