| Term | Definition |
| Federalism | System of government where power is shared between state governments and a national government. |
| Unitary System | System of government where power is held by a central government. |
| Confederation | System of government where state or regional governments hold power over a central government. |
| Delegated Powers | Powers granted to the national government. |
| Concurrent Powers | Powers shared by state governments and the national government. |
| Expressed Powers | Powers specifically granted to the national government in the Constitution. |
| Implied Powers | Powers of the national government "hinted at" in the Constitution that are not specifically stated. |
| Inherent Powers | Powers held by the central government because it is a central government. |
| Reserved Powers | Powers held by the state governments. |
| Elastic Clause | Term based on the words "necessary and proper" in Article I, Section 8. |
| 10th Amendment | Reserves powers not granted to the national government for the states. |
| Ex Post Facto Law | Laws created "after the fact" that are prohibited by the Constitution. |
| Interstate Commerce | Trade or business that crosses state borders. |
| Intrastate Commerce | Trade or business that does not cross state borders. |
| Dual Federalism or "Layer Cake" Federalism | Form of federalism where state and national responsibilities are clearly defined. |
| Cooperative Federalism or "Marble Cake" Federalism | Form of federalism where state and national responsibilities often overlap. |