In a federal system, the central (or federal) government has much more authority than in a confederal system. The central government controls more trade policy, and makes decisions about policy areas that involve interactions between states (such as highway systems).
Nationality is a legal relationship between an individual person and a state. Nationality affords the state jurisdiction over the person and affords the person the protection of the state. What these rights and duties are vary from state to state.
Definition: Ethnicity is a concept referring to a shared culture and way of life. This can be reflected in language, religion, material culture such as clothing and food, and cultural products such as music and art. Ethnicity is often a major source of social cohesion and social conflict.