world of form ［色界］ (, Pali rūpa-dhātu; shiki-kai): Also, world of matter. The middle division of the threefold world, located above the world of desire. Beings in this realm have physical bodies and are subject to certain material restrictions, but are free of desire and feed on light. The world of form consists of the four meditation heavens and is further subdivided into eighteen heavens (sixteen or seventeen according to other explanations). The highest is the Akanishtha Heaven, or Summit of Being Heaven. The Sanskrit word rūpa means form, outward appearance, color, phenomenon, or thing, and dhātu means world or realm. See also eighteen heavens; four meditation heavens.