Law is a system of rules that dictates the behavior of members of a society. It is enforced by a government and often carries heavy penalties for violations. Law shapes politics, economics, history and society in many ways. Law definitions vary by country, but there are a few key elements to consider.

Laws are typically created by legislatures or by courts. Some countries, such as the United States, use a common law system in which the legal system is based on judicial decisions instead of legislative statutes. Judicial decisions are compiled into case law, which is binding on other courts unless they can prove the decision was wrong. Other countries, such as Japan, have a civil law system in which a set of legal statutes clearly define the cases that can be brought to court and what punishments are available for certain offenses. Judicial decisions still exist in these systems, but they are not binding on other courts unless they can prove that the case was unfair or that the laws were wrongly applied.

Other countries have a combination of both common and civil law systems, with some legislating specific types of cases and allowing judges to decide other cases on their own. A person who studies law can find jobs in the fields of criminal, administrative, labor, corporate, environmental and constitutional law. There are also fields of law that deal with specific groupings, such as family or property law, or that have a more general scope, such as international law.

A law may describe a legal procedure, such as the discovery process in which lawyers examine each other’s information before trial, or it could be a statute that sets out a particular right, such as the freedom of expression or the right to privacy. There are also laws that govern the relationships between people, such as marriage law or divorce law. Laws that govern business and industry include banking, financial, insurance, tax and securities laws. Some laws are societal, such as environmental, consumer, health and safety and human rights laws.

The word law can be used to describe any strong rule made by an authority that must be obeyed, even if it is not officially written down and enforced. A simple example would be a parent’s house rules, which could be described as law. Laws can be applied to individuals, groups or companies and are sometimes called a code of conduct. A person who wants to practice law must undergo a specified course of study, complete professional training and pass a legal exam. Lawyers are given a professional title, such as Esquire or Doctor of Laws, and are usually overseen by a government agency or independent regulating body. There are a number of alternative terms for the law, such as morality and ethics, which have less to do with formal legal procedures than with principles that should guide a person’s actions.