(literary) a low screen wall standing inside the gate of a palace in traditional Chinese architecture; used to shield the interior from view

(literary) used figuratively to refer to one's internal affairs, the inside of a house, or one's own side or group

(literary) used metaphorically to refer to internal strife or domestic conflict, as in the idiom 祸起萧墙 huò​qǐ​xiāo​qiáng