运行
yùn xíng · HSK 5
to operate
🚆 运 = transport + 行 = go/move; together = to run/operate
运 carries the sense of moving or transporting (as in 运送 transport), and 行 means to go or move along. Combined, they describe something running its course — a train operating, a system functioning, or planets moving.
运 — walk radical 辶 + 军 jūn (army)
Originally depicted an army (军) on the move (辶), meaning to transport or move troops. The sense broadened to 'transport, move, revolve' and later acquired the abstract meaning of 'fortune' or 'luck'—what fate moves toward you. The simplified form replaces traditional 運.
行 — crossroads pictograph (left 彳 + right 亍)
行 originally pictured a four-way crossroads in oracle bone script, with two paths meeting. From 'road' it extended to 'walk, go, travel,' and then to 'a row, line' or 'business firm' (read háng). The two halves 彳 and 亍 are the split sides of that ancient crossroads.