开动
kāi dòng · HSK 7
to move
🚜 开动 = 开 (open/start) + 动 (move): open up the moving, set it in motion
开 carries the sense of start/open and 动 means move or motion, so 开动 literally stacks start onto move. Used for kicking off a machine, an engine, or even troops on the march.
开 — two hands 廾 + door 门 (open gate)
Originally written 開, showing two hands (廾) lifting the bar (一) off a gate (門) to open it. The simplified form 开 keeps the two-hands element and drops the gate. Core meaning 'to open' extended to 'start, operate, bloom'.
动 — force 力 + heavy/重 (simplified from 動)
The traditional form 動 combines 重 (heavy) as the phonetic with 力 (force/strength) as the semantic, suggesting the effort needed to move something heavy. The simplified form 动 replaces 重 with 云, keeping 力 to convey action and motion.