Law is the system of rules a particular country or community recognizes as regulating their members’ actions. It encompasses a vast number of topics, from criminal and administrative law to tax and social security law. Its four principal functions are establishing standards, maintaining order, resolving disputes, and protecting liberties and rights. Some laws serve these purposes more effectively than others. For example, an authoritarian government may keep the peace and maintain the status quo, but it is unlikely to encourage democratic change or protect minorities from majorities.
The precise definition of law is a matter of controversy. It can be loosely defined as the set of regulations created and enforced by a state that forms a framework to ensure a peaceful society. It can be more precisely defined as the body of rules a court refers to in judging a case or deciding on punishment. It can also be seen as a body of regulations that governs a specific area of human activity, such as aviation or business transactions.
It is often divided into categories such as commercial, family, criminal and international law. In the former category are topics such as contracts, property and corporate governance. In the latter are such topics as immigration and nationality law, which concern the right to work in a nation-state and to acquire or lose citizenship; and constitutional law, which defines the fundamental structure of the state and determines the rights and duties of its citizens.
In the law of nations, the distinction between common and civil law has historically been significant. Although there is much cross-fertilization of ideas between the two traditions, their basic processes and forms of reasoning remain distinct.
There are many other legal systems, such as those based on religious precepts such as Jewish Halakha and Islamic Sharia. These typically have the added dimension of further human elaboration through interpretation, Qiyas (reasoning by analogy) and Ijma (consensus).
The practice of law is often overseen by a governing authority or independent regulating body such as a bar association, bar council or law society. Modern lawyers achieve their distinct professional identity through specified legal procedures, usually including the successful completion of a legal education earning them a Bachelor of Laws or Juris Doctor degree.
The legal system of a country is largely determined by its history, connections with other countries and adherence to international law. In addition, its political landscape influences the nature of its laws. For example, the separation of powers between legislative, executive and judicial branches is a central feature of American law. This arrangement is rooted in the Constitution, which was written to counterbalance monarchical rule and prevent one individual from becoming an absolute tyrant over his subjects. In many other nations, this balance is achieved through a different means, such as tribal or local customs. Despite these distinctions, the fundamental principles of the law are broadly similar across nations and communities. The Oxford Dictionary of Law includes entries on these differences, and describes the way in which law is conceived and used by each community.