Refers specifically to the capital city of an empire, often used in historical or formal contexts. In modern Japanese, it is strongly associated with Tokyo during the pre-war period when Japan was an empire.
帝都東京は、かつて日本の政治と文化の中心だった。
The imperial capital Tokyo was once the political and cultural center of Japan.
This novel is a historical tale set in the imperial capital.
Compound of 帝 (てい, 'emperor') and 都 (と, 'capital'). The word has been used historically to refer to the capital of an empire, and in Japan it became a common designation for Tokyo during the Meiji to early Showa periods.