銅牆鐵壁 tóng qiáng tiě bì

DEFINITIONS

  1. copper wall, iron bastion (idiom); impenetrable defense

CHARACTERS

銅 tóng copper, brass, bronze cuprum
牆 qiáng wall
鐵 tiě iron; strong, solid, firm
壁 bì
HSK 5
partition wall; walls of a house