一切經音義 50.242

50.242

青淤（下於句反考聲淤水中凝泥也顧野王云今水中泥草為淤也說文澱滓也從水於聲也）。

Green sludge (青淤; the second character is pronounced with the fanqie 于 + 句 [yù]. The Kaosheng says: "'Sludge' (淤) is coagulated mud in water." Gu Yewang says: "Nowadays, the mud and weeds in water are considered sludge." The Shuowen says: "Sediment and dregs." It is formed with the water semantic and 於 as phonetic).