Zi Collection, Upper Volume Radical: Mouth (kǒu) Page 15, Entry 03 Pronounced du (falling tone) Meaning: Buttocks — Explanation from "Tongya" (Boyao) This character is the same as another character — "Zihui" (Zihui) This is a vulgar character — "Zhengzitong" (Zhengzitong) Detailed explanation can be found in the commentary on another character.