銅牆鐵壁 Save Sign in to save words Simplified: 铜墙铁壁 tóngqiángtiěbì ㄊㄨㄥˊ ㄑㄧㄤˊ ㄊㄧㄝˇ ㄅㄧˋ copper wall, iron bastion (idiom) impenetrable defense Character by character 銅(tóng)copper 牆(qiáng)wall 鐵(tiě)surname Tie 壁(bì)wall A Chinese word or character, or English Search Sources CC-CEDICT, CC BY-SA 4.0 pinyinjs, Apache-2.0