metro-³

A capital city or other large urban area.

The first part of metropolis, from Greek mētēr, mētr‑, mother, plus polis, city.

Someone or something metrocentric is biased towards the affairs or interests of the capital city; and a metroplex (see ‑plex) is a very large metropolitan area, especially one which is an aggregation of two or more cities. The form has become a word in its own right, metro (originally as French métro), to describe an underground or light railway system in a large urban area.