- This article is about a term for the centre of the British Empire. For other uses, see Metropol.
The metropole, from the Greek metropolis for 'mother city' (polis, from the Greek for city, is understood in this context to indicate a city state, and is hence also used for any colonizing 'mother country'; in ecclesiastical usage, metropole usually denotes an archbishopric having precedence over the suffragans in its ecclesiastical province) is a term used to indicate the British metropolitan centre of the British Empire, i.e. the United Kingdom itself. It is sometimes extended even further, in the sense of London being considered the metropole of the British Empire, insofar as its politicians and businessmen determined the economic, diplomatic, and military character of the rest of the Empire. By contrast, the periphery was the rest of the Empire, outside the United Kingdom itself.
Metropole and periphery 
The historiography of British metropole-periphery relations has traditionally been defined in terms of their distinct separation, with a pronouncedly one-way, near-dictatorial channel of command, communication and control proceeding outward from the center; the metropole informed the periphery but the periphery did not directly inform the metropole; hence, the British Empire was constituted by the formal control of territories, by direct rule of foreign lands, instigated by the metropole.
More recent work, starting with that of John Gallagher and Ronald Robinson in the 1950s, has questioned the traditional definition, positing instead that the two were mutually constituitive and maintaining that despite the apparent temporal inconsistencies inherent in their separate existences, each formed simultaneously in relation to the other. Gallagher and Robinson were socialists, observing the rise of the economic power of the United States in the developing world at a time when the African colonies of the British Empire were being granted independence; both scholars held that British and American 'empires' were ultimately developed along similar lines.
In the context of Gallagher, Robinson, and Adlai Stevenson's theories of 'free trade imperialism', the use of soft power, primarily through the employment of British capital, allowed the United Kingdom to extract concessions, namely free trade for British manufactured goods, just as readily as if they had engaged in a costly military occupation of the territories. In this interpretation, the economic informal Empire of the periphery constituted a formal 'Empire' just as surely as the metropole did.
Other empires 
Such cognate words as métropole (French) and metrópole (Portuguese) designate the main part of a country, usually on the European continent, as opposed to its colonial possessions and/or overseas territories:
- In the case of present-day France, the term refers to Metropolitan France—i.e., France without its overseas departments and other territories.
- For Portugal, during the period of the 19th and 20th centuries, Metrópole designated the European part of Portugal (Mainland Portugal along with the Azores and Madeira); the overseas provinces were known as Ultramar (= overseas). Until 1975, Portuguese Africa's Ultramar referred to Angola, Mozambique, Portuguese Guinea, Cape Verde and São Tomé and Príncipe. The term Metrópole was dropped from common usage in the mid-1970s when the Portuguese colonies in Africa (now known as the PALOP [for 'Países Africanos de Língua Oficial Portuguesa'], also referred to as Lusophone Africa) achieved independence. Outside of Africa, Portuguese India, Macau and Portuguese Timor were also part of Ultramar.
- In the Dutch Empire, from the 17th through the 20th centuries, the metropole consisted of the European territories of the Dutch 'homeland' (under the various political incarnations after 1581, the United Provinces, the Batavian Republic, the United Kingdom of the Netherlands, and the Kingdom of the Netherlands), while the periphery consisted of the far-flung settlements and colonies of both the Eastern and Western hemispheres, including the Dutch East Indies and the 'Spice Islands' (primarily, the Moluccas and the Banda Islands) in the 'east', along with Suriname, and the Dutch West Indies (primarily, Aruba, Bonaire, Curaçao, Saba, Sint Eustatius and Sint Maarten), in the 'west'.
Other countries use different designations. See also Mainland
- The Contiguous United States, often referred to as the "Lower 48", might be considered the United States' equivalent of the Metropole. (This contiguous area includes 48 of the country's 50 states and the District of Columbia.) Two states (Alaska and Hawaii) and a few territories (such as Puerto Rico, the United States Virgin Islands, and Guam) lie outside of this area.
- Naichi is Japan's equivalent. It was used in antebellum Japan to distinguish the Japanese archipelago from Japan's colonies (Gaichi); modern usage of the term by residents of Hokkaido and Okinawa sometimes refer to "Naichi" as being the central islands outside of Hokkaido and Okinawa.
- Peninsular Malaysia - for the "mainland" of Malaysia.
- Manner-Suomi - Finland's mainland, as opposed to Åland.