Law is a system of rules that regulates the conduct of people in a community and is enforced by penalties. The word is most often used to refer to the rules of a state or nation, but it may also be applied to a religious or moral code or a set of principles for governing an economy.

The four principal purposes of the law are establishing standards, maintaining order, resolving disputes and protecting liberties and rights. The way these are accomplished varies from place to place. A stable and democratic political structure, for example, requires laws that are transparent and well-researched. It is essential that the rule of law be followed by all people, regardless of their wealth or status. It is also necessary that law be clear and accessible, so that everyone understands the expectations of society.

Legal practice includes advising and representing people about the law and defending them in court. Lawyers are called a variety of names, such as Esquire, Barrister or Doctor of Law.

Laws affect everyday life in a multitude of ways and are found throughout all types of businesses, industries and organizations. Laws regulating air and maritime transportation, the sale of goods and the management of public utilities are examples. Intellectual property laws protect creations that people create, such as art or music, and they help to define the rights that individuals have over their personal property. Business laws establish rules about how companies must invest their capital, while tort law helps people claim compensation when they are harmed or have their property damaged, for example in an automobile accident.