capital city; capital; metropolis
Refers to the main city that functions as the seat of government of a country or comparable political unit. The gloss 'metropolis' is only appropriate when the city is also a major central city.
The capital of Japan is Tokyo.
政府は首都に新しい庁舎を建てた。
The government built a new office building in the capital.
The capital of Japan is Tokyo.
The government is considering relocating the capital.