一切經音義 5.206

5.206

浮囊（上附無反孔注尚書云泛流曰浮汎也芳劒反賈逵注國語云浮輕也下奴即反說文囊橐也音託案盛氣皮袋也憑浮囊而渡大水氣囊也經取輕浮為言喻也）。

Float bladder (浮囊: the first character has the fanqie 附無反; Kong [Anguo's] commentary on the Shangshu states: "Drifting upon the flow is called fu (浮)." Fu means floating (fanqie 芳劒反). Jia Kui's commentary on the Guoyu states: "Fu means light." The second character has the fanqie 奴即反; the Shuowen jiezi states: "Nang (囊) means a sack (橐, sound 託)." Note: it refers to a leather bag filled with air; one relies on the floating bladder to cross great waters. It is an air-skin. The sūtra takes its lightness and buoyancy as a metaphor).