Law is the set of rules and principles imposed by a government or other authority for the control and direction of an organization, a society, or a nation. It includes the body of laws governing a particular subject area, as well as specific statutes and constitutional provisions establishing the legal status of an individual or group. The study of the development, administration, and interpretation of law is called jurisprudence. The profession that deals with legal issues and procedures is called the law profession or, more broadly, the legal profession.
Law serves many purposes, and different nations have different arrangements for achieving them. Four of the most important are establishing standards, maintaining order, resolving disputes, and protecting rights and liberties. The degree to which a country succeeds in meeting these goals depends in part on the balance of power between the different branches of its government.
A basic principle is that no one, including the king or president of a state or nation, is above the law. This is sometimes referred to as the rule of law or the supremacy of the law. The concept is central to constitutional republics and other democratic forms of government.
The term law is sometimes used to refer to a system of natural processes or a natural order whose operation is predictable and consistent: the law of gravity; the laws of thermodynamics; the law of supply and demand. In addition, the law may be used to describe a system of ethical behavior or moral guidelines based on conscience, concepts of natural justice, or the will of a deity: a code of law; the law of love.
An important function of the law is to regulate economic and social change. For example, the legal system may allow for the formation of companies or trusts; establish the status of partners; limit the liability of shareholders; and define the rights of workers and employers. A country may also have a special law relating to real estate and property transactions.
A court of law is an institution that decides cases through a process of testimony and evidence. The presiding judge or jury decides whether a defendant is guilty or not guilty of a crime and imposes punishment, if necessary. Appeals are requests to have another court review the ruling of a lower court or tribunal. Evidence presented in a case includes written documents, physical objects (such as weapons or contracts), and oral testimony. The judge and jury examine the exhibits in the course of a trial. An exhibit that tends to exonerate a defendant is often called exculpatory evidence. Federal courts have jurisdiction over cases involving the interpretation and application of the Constitution, acts of Congress, and treaties. The term federal question is also used to distinguish a matter from a state law.