一切經音義 25.25

25.25

三千大千（一四天下一日月照臨名一世界即此千世界名一小千一千小千名一中千一千中千名一大千故云三千大千也其數百億億有三等如第四卷釋）。

'Three-thousand great-thousand' [trisāhasramahāsāhasra] (One set of four continents illuminated by one sun and moon is called one world system; one thousand such world systems are called a small-thousand; one thousand small-thousand are called a medium-thousand; one thousand medium-thousand are called a great-thousand; hence it is called three-thousand great-thousand. Their number is ten billion; there are three tiers of 'billion' [yì], as explained in Fascicle 4).