当成
dāngchéng · HSK 6
regard as
当 = treat as + 成 = become; together: treat-as-become = regard as
当 here means 'treat/serve as' and 成 means 'become/turn into'. The compound 当成 literally reads 'treat-as-become', i.e. to take one thing and let it count as another — regard as, consider as.
当 — small ⺌ + crown 冖 + hand 彐 (simplified from 當: 尚 + 田)
Originally written 當, combining 田 'field' with 尚 as a phonetic. The early sense was 'to match' or 'face' a field of equal value, extended to 'correspond to', 'ought to', and 'serve as'. The simplified form 当 streamlines the upper 尚 component.
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.