hamlet — a rural community too small to be considered a village (from the French)
village — usually rural, larger than a hamlet, smaller than a town (from the French)
town — ranging from a few to several thousand (occasionally hundreds of thousands) inhabitants (from the German)
city — an urban area with large population (from the French)
metropolis — a large city, usually has suburbs (from the Greek)
megalopolis — a long chain of roughly continuous metropolitan areas/cities
also “township” and “borough” (from the German)
ekistics = the scientific study of human settlements and the planning and design of such settlements (cities/communities)