Name of the people: Terran (sing.) / Terrans (pl.)
Terra, called Earth long ago by humans before they became a star-faring race, is the centre of human civilisation and the the birthplace of humanity. It is the focal point of a great number of things that define humanity: politics, trade, commerce, military strength, science, culture and much more. Since taking to the stars humanity hasn't walked an easy road, but through as much luck as skill Terra has remained untouched by war. It is the headquarters of the Terran Sovereignty Army, the Terran Sovereignty Navy, Terran Special Operations, and has a branch of the enigmatic Adept Program.
Life on Terra for civilians is, for the most part, comfortable. As the wealthiest planet in human-occupied space many people have more than enough to get by. Many citizens of Terra will dress in the latest fashions, whatever that may be at the time, and all types of consumer goods and luxuries are widely available. Constant development of Terra has led to overpopulation issues, which in turn has caused the construction of millions of square miles of geocentrically orbiting habitats (habs) connected by space elevators. The quality of these habs is directly proportional to the cost of living there, meaning many of the poorer citizens of Terra are forced to live in the more cramped and less pleasant habs.
There are few native Terrans in the Segovax cluster, as the long distance between Terra and any of the Segovax cluster colonies requires travellers to enter cryo-sleep for 80 years in order to reach their destination. Yet a few desperate souls are willing to forsake everything they knew for a chance at a new adventurous life on the fringes of human civilisation. People from Terra are usually proud and patriotic. They have not only seen but been a part of the best that humanity has to offer. This means, however, that they tend to have an unrealistic view of the rest of the Sovereignty. Some of the more conspirational individuals doubt the war exists at all, and believe it to be a propaganda tool of the Sovereignty. Few, however, agree with this view.
The reach of Terra in the Sovereignty is long, but out here on the very edge of human endeavor it is somewhat diluted. Most know that they will never see their leaders or even Terra itself, for to take the journey is to lose everyone you have known. However all acknowledge that it is the heart of humanity in the cosmos and must be protected at all costs.
Inspiration for characterisation: city-planets, Rome, high-culture, Capital (Hunger Games), Xandar (Guardians of the Galaxy).