Final answer:
The sharing of legal jurisdiction between multiple courts in the United States' legal system is known as the dual court system.
Step-by-step explanation:
The question refers to the concept of dual court system in the United States' legal system. The U.S. judicial system features both federal courts and state courts, and each level has its own distinct jurisdiction. The federal courts have jurisdiction over cases involving federal law, disputes between states, and disputes between residents of different states. On the other hand, state courts have jurisdiction over matters that fall under state law.