Law is the set of rules created and enforced by social or governmental institutions to regulate behavior. Its precise definition is a matter of longstanding debate and has been variously described as a science and as the art of justice. Law is a normative discipline, in contrast to empirical sciences such as physics or even social sciences such as economics which have descriptive properties (such as gravity). Law also has prescriptive properties; it dictates how people ought to behave or what they may or must not require of others. These two features of law make it a unique and challenging subject to study.
The study of law encompasses a broad range of subjects from criminal law, tax law and civil rights to international law, family law, and labor law. Oxford Reference offers a comprehensive collection of more than 34,000 concise definitions and in-depth, specialist encyclopedic entries, written by trusted experts, covering all aspects of this vast discipline.
Whether it is a statute or common law, the rule of law is the premise upon which societies organize themselves. This premise includes the principle that all persons and institutions are accountable to laws which are publicly promulgated, equally enforced, and independently adjudicated. In addition it requires measures to ensure legal certainty, transparency and participation, avoidance of arbitrariness and a rigorous judicial review process.
Legal systems vary across the world, with some countries maintaining civil law traditions which are distinct from the common law. In other cases, legal systems combine elements of both civil and common law. For example, African nations retain elements of the Roman-Dutch law tradition, while countries of the Pacific retain a mixture of civil and common law.
Civil law systems generally have a more legislative structure than common law systems, with legislatures creating a wide variety of laws in different areas of the country. Common law, on the other hand, is largely derived from judicial decisions. This makes it easier for judges to interpret and apply the law to new situations.
In either type of legal system, there is no guarantee that the rules are accurate or complete. For this reason, lawyers spend a lot of time researching and studying caselaw and other sources to stay current on the latest developments in the law.
In some jurisdictions, a person who is the subject of a lawsuit has the option to ask an appeals court to decide whether the trial was conducted properly. This is known as an appeal, and the party who makes the request is called an appellant. Generally, a court of appeals is composed of three judges, but it can be expanded to a full bench in cases it deems important enough to consider. This is called sitting en banc. An appeals court can reverse a lower-court decision, or it can uphold the ruling. A reversal usually happens only if the appellant can show that the original court misinterpreted or applied the law incorrectly. A reversal is sometimes called a reversal de novo.