"Tang Yun" pronounced with the tones of 'fang' and 'gou' as the initial and final respectively, with a rising tone. "Shuowen Jiezi" explains it as the place where clothes are tied. Also, "Jiyun" pronounced with 'bi' and 'kou' as the initial and final respectively. The meaning is the same. Sometimes also written as 'fu'. According to "Haipian," it is directly pronounced 'bao', which does not correspond to the rhyme schemes above.