| 墙 | qiáng | wall (CL:面[mian4],堵[du3]) / (slang) to block (a website) (usu. in the passive: 被牆|被墙[bei4 qiang2]) |
| 堵 | dǔ | to block up (a road, pipe etc) / to stop up (a hole) / (fig.) (of a person) choked up with anxiety or stress / wall (literary) / (classifier for walls) |
| 防火墙 | fáng huǒ qiáng | firewall / CL:堵[du3] |