"Tang Yun" uses "yi zhou" for pronunciation, "Ji Yun" and "Yun Hui" use "yi zhou" for pronunciation, "Zheng Yun" uses "yu qiu" for pronunciation, pronounced "you". "Shuowen Jiezi" explains it as a tree sprouting branches. The character shape comes from "gong", resembling branches and buds, with "you" indicating pronunciation. Cites "Shang Shu" saying "Ruo dian mu zhi you niu niao". "Xu Yue" explains this refers to a fallen tree that has sprouted new branches. "Niu" means "still able to" or "only to this extent". "Jin Wen Shang Shu" writes it as "you".