metrópole

emämaa A metropolis; the main city of a country or area. (defdate)
The parent-state of a colony. (defdate)
2007, Bruce Ackerman, ‘Meritocracy v. Democracy’, London Review of Books 29:5, p. 9:

Though the metropole remained confident in its Westminster ways, its newly independent colonies imposed constitutional constraints on the powers of parliament.

As Europe's population growth and commercial activity slowed down after 1620, its thirst for Spanish-American silver slackened: metropole and colony were drifting apart.