According to the Tang Rhyme (Tangyun) and the Jade Chapters (Yupian), the pronunciation is wu. According to the Collected Rhymes (Jiyun), the pronunciation is yu. The pronunciation is the same as the word wo. The meaning is to rub. Additionally, according to the Collected Rhymes (Jiyun), the pronunciation is e. The pronunciation is the same as the word e. The meaning is the same.