New, essentially self-sufficient settlements, usually modest in size, which are built in a previously undeveloped area. Their purpose is typically to provide residential, commercial, industrial, educational, recreational, and public facilities for larger urban areas. The term is often reserved for such settlements sponsored or approved by a government and created in a rural or undeveloped area to absorb overspill population from a nearby large city. Examples of new towns are the planned communities of the New Towns Movement in the United Kingdom after World War II, for which communities were purposefully planned, developed, and built to alleviate overcrowding in large cities.

Source: AAT

http://vocab.getty.edu/page/aat/300008377