Zi Collection, Middle Volume. Radical: Person (rén). Character: You. Kangxi Stroke Count: 7. Page Number: Page 98, Number 11.
According to Collected Rimes (Jiyun) and Compiled Rimes (Yunhui), the pronunciation is derived from the sounds yun and jiu, pronounced as you. It means to assist or to aid.
Furthermore, according to Collected Rimes and Corrected Rimes (Zhengyun), this character is identical to the character you (spirit radical). As recorded in the Book of Documents (Shujing) in the Announcement of Tang: High Heaven provides sincere protection to the common people.
It is also used as a rhyming pronunciation derived from the sounds yu and kui, sounding like wei. In the Songs of the South (Chuci) in the Heavenly Questions: Why did the deer bless the woman gathering ferns? Reaching the northern circling waters, why was there such joy? The commentary notes that the spirit radical version is sometimes written as the person radical version. The character for joy is read here with the rhyming pronunciation xi.
According to Explaining Graphs and Analyzing Characters (Shuowen Jiezi), the character for assisting was originally written as the character for right hand, pronounced you. The person radical has since been added to form the current character you, which is pronounced you. Meanwhile, the character for right hand is now restricted to the meaning of the right hand, which no longer reflects the original meaning as explained in Shuowen Jiezi.