In politics, a capital (also called capital city or political capital — although the latter phrase has an alternative meaning based on an alternative meaning of "capital") is the principal city or town associated with its government. It is almost always the city which physically encompasses the offices and meeting places of the seat of government and is usually fixed by law. The word capital is derived from the Latincaput meaning "head," and possibly related to Capitoline Hill, the tallest hill in Ancient Rome and that city's religious and historic center.
Capital cities in NationStates are the seat of government for most nations, and as such they feature prominently in most diplomacy-based roleplay. However, a number of players will have nations with many cities, towns and other areas of population, so it does not always follow that all action will take place there. They are not automatically important; the owner has to make that so.
If you are engaging another nation in roleplay and you need to mention a city from their nation, it is normally safe to start with their capital city.