一切經音義 1.74

1.74

神甸（亭現反鄭玄注周禮云甸猶田也天子服治之田也孔注尚書云規方千里之內謂之甸服王城四面各五百里也今謂之畿甸即是也畿音祈）。

Shendian (ting-xian fan; Zheng Xuan's commentary on the Zhouli says: "Dian is like tian (field); it is the field cultivated to serve the Son of Heaven"; Kong's commentary on the Shangshu says: "The territory within a square of one thousand li is called the dianfu, extending five hundred li on each of the four sides of the royal city"; what is nowadays called jidian [capital domain] is precisely this; ji is pronounced qi).