Arcology, a portmanteau of "architecture" and "ecology", is a vision of architectural design principles for very densely populated habitats. The concept has been primarily popularized, and the term itself coined, by architect Paolo Soleri. It also appears in science fiction. These structures have been largely hypothetical insofar as no 'arcology' envisioned by Soleri himself has yet been completed, but he posited that a completed arcology would provide space for a variety of residential, commercial, and agricultural facilities while minimizing individual human environmental impact. Arcologies are often portrayed in sci-fi as self-contained or economically self-sufficient.
An arcology is distinguished from a merely large building in that it is designed to lessen the impact of human habitation on any given ecosystem. It could be self-sustainable, employing all or most of its own available resources for a comfortable life: power; climate control; food production; air and water conservation and purification; sewage treatment; etc. An arcology is designed to make it possible to supply those items for a large population. An arcology would supply and maintain its own municipal or urban infrastructures in order to operate and connect with other urban environments apart from its own.