Capital planet
A capital planet was the planet exercising primary status in an empire, star system, or other administrative region, usually as its seat of government. Romulus was the capital planet of the Romulan Star Empire. ()

In Carls edition of the The Star Dispatch, the capital planets of the Terran Empire and the Tkon Empire were referred to as throne worlds. ()

In 2380, the  visited Galardon, the capital planet of the Galar system, to meet with members of the Galardonian High Council. ()

List of capital planets 
  (Breen Confederacy)
 Cardassia Prime (Cardassian Union, Cardassian Zone)
 Earth ()
 Ferenginar (Ferengi Alliance, Ferengi Territory)
 First Founders' homeworld (Dominion)
 Iconia (Iconian empire)
 Lysia (Lysian Alliance)
 Qo'noS (Klingon Empire, Klingon Zone)
 Romulus (Romulan Star Empire)
 Sheliak homeworld (Sheliak Corporate)
 Talarian homeworld (Talarian Republic)
 Terra (Terran Empire)
 Tkon throne world (Tkon Empire)
 Vidiian homeworld (Vidiian Sodality)

See also 
 Capital city
 Homeworld
Government