一切經音義 7.5

7.5

源底（上愚袁反禮記云達於禮樂之源鄭玄曰源本也廣雅萬物之本曰源說文作厡或作原古字也）。

源底 ("source and bottom"): The first character has the fanqie reading [ŋ- + -ʉɐn = yuán] (愚袁反). The Liji says: "Penetrating to the source of rites and music." Zheng Xuan says: "源 means root." The Guangya says: "The root of the myriad things is called 源." The Shuowen writes it 原, or 原, which are ancient characters.