triple-thousand great thousand worlds　三千大千世界 The world system as conceived in Buddhist cosmology. It consists of the three kinds of “thousand-worlds”: small, medium, and great. The basic unit is called a “Sumeru-world”. A thousand such units constitute a small thousand-world. A thousand small thousand-worlds constitute a medium thousand-world. A thousand medium thousand-worlds constitute a great thousand-world. A great thousand-world is regarded as the domain reigned over by one Buddha. See Mount Sumeru.