There are many ways to define the Three Thousand Worlds.
In Lu Bei's original plan, a single leaf, a flower, or a blade of grass was a Small World. Beyond flora and fauna, the sun, moon, and stars all fit the conceptual framework of a Small World. By defining one thousand as a base unit, one thousand Small Worlds formed a Small Thousand World. One thousand Small Thousand Worlds made up a Medium Thousand World, and one thousand Medium Thousand Worlds made up a Great Thousand World. Because they progressed in layers from small to large, they were known as the Three Thousand Worlds.
Countless worlds formed a multi-dimensional cosmic space, extending and diffusing from the Great Central World as the core. The dimensions were infinite, and the Three Thousand Worlds were likewise countless. Thus, the Heavenly Emperor, the Great Heavenly Venerable, governed all heavens!
Chapter 1018