俱舍論頌疏論本 11.63

11.63

釋曰：千四大洲乃至千梵世，如是總說為一小千。千倍小千，名一中千界。千中千界，總名大千界。如是大千同成同壞。

Explanation: A thousand of the four great continents, up to a thousand Brahma worlds—such in total is called one small-thousandworld. A thousand times a small-thousandworld is named one medium-thousandworld. A thousand medium-thousandworlds in total are named a great-thousandworld. Such a great-thousandworld shares the same creation and destruction.