Arcology

Arcology, a portmanteau of "architecture" and "ecology", is a field of creating architectural design principles for very densely populated, ecologically low-impact human habitats.
The concept has been primarily popularized, and the term itself coined, by architect Paolo Soleri. It also appears in science fiction. Authors such as Peter Hamilton in Neutronium Alchemist or Paolo Bacigalupi in The Water Knife explicitly use arcologies as part of their scenarios. Arcologies are often portrayed in science fiction as self-contained or economically self-sufficient.
These structures have been largely hypothetical insofar as no arcology, even one 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.