Jurisdiction is the power or authority of a court to hear and try a case; the geographic area in which a court has power, or the types of cases it has power to hear.
Explained another way, jurisdiction is the legal authority of a court to hear and decide a case that arose in a certain geographic area or a certain type of case. It is closely related to venue, which refers to the specific court where it is most proper to have a case heard. In a particular case, multiple courts may have jurisdiction, and the rules of venue determine which particular court with jurisdiction will hear the case.
For example, if a landlord wants to sue a tenant for eviction, generally such a matter is brought before a justice of the peace or a small claims court, as opposed to a probate court. On the other hand the heirs in a probate matter generally must have the case heard within a probate court as opposed to a small claims court.
In the United States, jurisdiction is separated into two separate types: personal jurisdiction and subject matter jurisdiction. Personal jurisdiction is the authority of a court to enter a judgment against a particular person. Subject matter jurisdiction is the authority of a court to enter judgments on a particular subject. Some courts, such as federal district courts are courts of general jurisdiction and can enter judgments on nearly any area of federal law. Other courts, such as state family courts, are courts of limited jurisdiction and may only enter judgments on certain subjects.