許慎
In classical Chinese philology, shengxun (聲訓 "voice explanation") or yinxun (音訓 "sound explanation") is the practice of explaining a character by using a homophone or near-homophone. The practice is ancient, and can be seen in pre-Qin texts. Xu Shen, author of the monumental "Shuowen Jiezi", employed "shengxun". For example, when Xu explained the word "ghost", he wrote: