Metropolis
METROP'OLIS, noun [Latin from Gr. mother, and city. It has no plural.]
Literally, the mother-city, that is, the chief city or capital of a kingdom, state or country, as Paris in France, Madrid in Spain, London in Great Britain. In the United States, Washington, in the District of Columbia, is the metropolis as being the seat of government; but in several of the states, the largest cities are not the seats of the respective governments. Yet New York city, in the state of that name, and Philadelphia in Pennsylvania, are the chief cities, and may be called each the metropolis of the state in which it is situated, though neither of them is the seat of government in the state.