Law is a set of rules that social or governmental institutions create and enforce to regulate behavior. Its precise definition is a matter of longstanding debate. Some philosophers have characterized it as an art and as a science. Others have focused on its functions, which include keeping the peace, maintaining the status quo, preserving individual rights, protecting minorities against majorities, and promoting social change.

Having a clear, publicized, and stable legal system is essential for achieving these functions. A legal system also must ensure that its application is equitable, that it safeguards human rights, and that the process of adopting, administering, interpreting, and adjudicating the law is accessible, fair, and impartial.

Many people have a deep interest in law, whether as a career or as a way of life. Lawyers work with the rules that govern a society, while judges and police officers enforce them. In the United States, there are numerous fields of law, including contract law, criminal law, tort law, property law, and administrative law. Each field has its own experts, each specializing in an area of the law that deals with specific issues and situations.

The word “law” derives from the Latin nomos, meaning command or rule. It can refer to instruction in general or to a particular set of commands or regulations. In the Bible, the word law is used in a number of ways. The Old Testament scriptures focus on the commandments and rules in the Pentateuch, and the New Testament emphasizes Jesus’ teachings.

In modern English, the term law is most often used to describe the legal profession and the practice of resolving disputes through courts. The statutory law in the United States is written by Congress, and the constitutional law is established by the Supreme Court. Other countries have different systems of law. For example, civil law systems, which are found on most continents and cover about 60% of the world, are based on concepts, categories, and rules that are derived from Roman law and canon law and supplemented or modified by local custom and culture.

A key concept in understanding law is the notion of law as a tool for managing societal conflict. Law provides a framework of principles that help us decide who is right and what should be done in a dispute. For example, the law of war provides a framework for regulating military conflicts, and the laws of negligence or fraud provide guidelines for deciding civil claims.

Many different kinds of law exist, reflecting the variety of interests, values, and concerns that are reflected in human societies. For example, contracts are governed by contract law, while tort law focuses on the protection of individuals from others’ wrongful conduct. Property law, which is most prevalent in the United States, covers a wide range of issues related to individuals’ attachments to tangible things. For example, the law of trusts regulates relationships that involve a person’s money and other assets, and the law of real estate applies to land, buildings, and other physical objects.