一切經音義 57.245

57.245

姑妐（燭容反方言云今關中人呼夫之父曰妐考聲云妐亦夫之兄也從女從公聲也古文云爾）。

姑妐 (Father-in-law and mother-in-law; [妐 is] zh[u] + [rong] fan. The Fangyan says: "People of Guanzhong today call a husband's father 妐." The Kaosheng says: "妐 also refers to a husband's elder brother." It is derived from "woman" (女) with phonetic 公. So it is in ancient script).