Law is a body of rules, principles and practices that are enforced in a state or nation. It can be written or oral, and it can cover a wide range of topics from the rules on driving a car to the rules of a game. Law is the subject of study in a field called jurisprudence, and the practice of law is referred to as the legal profession.
Law can have many purposes, but four of the most important are establishing standards, maintaining order, resolving disputes, and protecting liberties and rights. Law can be natural, man-made, or both. Natural laws, such as the law of gravity, are universal in that they apply in every circumstance. Man-made laws are those devised by man that he believes is in the best interests of society as a whole.
Scientists use the term law to mean a scientific principle that can be proven: For example, the strength of the law of gravity between two objects (like an apple and the Earth) is a known quantity that depends on their masses and the distance between them. But the fact that a particular scientific principle is a law does not mean it can’t change through further research in the future.
Countries that do not have strong formal justice systems often rely on customary law. This is usually a mixture of traditional local practices that vary from community to community, and it is based on longstanding customs that greatly shape ideas about justice.