major world system ［三千大千世界］ ( trisāhasra-mahāsāhasraloka-dhātu; sanzen-daisen-sekai): Also, thousand-millionfold world. One of the world systems described in ancient Indian cosmology. A world consists of a Mount Sumeru, its surrounding seas and mountain ranges, a sun, a moon, and other heavenly bodies, extending upward to the first meditation heaven in the world of form and downward to the windy circle that is its foundation. This concept might be compared in modern terms to the concept of a solar system from the standpoint of the planet one lives on. One thousand worlds make a minor world system; one thousand minor world systems compose an intermediate world system; and one thousand intermediate world systems form a major world system. Therefore, one major world system comprises one billion worlds, and hence it is referred to as the thousand-millionfold world. The universe was conceived of as containing countless major world systems.