Zi Collection, Upper Volume, Page 46, Entry 03 Pronounced ao (entering tone). Recorded in the rhyme dictionaries "Tang Yun" (Tangyun), "Ji Yun" (Jiyun), "Yun Hui" (Yunhui), and "Zheng Yun" (Zhengyun) as "yu dao qie" (yu dao cut). "Shuo Wen Jie Zi" (Shuowen Jiezi) explains it as a warm vessel. Another explanation is a copper vessel. "Wu Yin Ji Yun" (Wuyin Jiyun) states it is a copper urn. "Bo Ya" (Boyya) says it is a "fu" (a type of pot). Furthermore, "Liu Shu Gu" (Liushu Gu) records that people today use the term "lao" for slow simmering to tenderize meat and other foods. Additionally, "Ji Yun" (Jiyun) records another pronunciation as "yi liu qie" (yi liu cut), pronounced "wu" (entering tone). The meaning is the same. This character was originally written as "fu".