Law is a system of rules that a society or government develops in order to deal with crime, business agreements and social relationships. Law is often enforced by a controlling authority through penalties such as fines or imprisonment. The term can also be used to describe the legal profession or the activities and decisions of those who work in this area, such as a judge or prosecutor.

Law can be created by a group legislature, resulting in statutes; by a single legislator through decrees and regulations; or established by judges through precedent (also known as case law). It may also be private and voluntary, for example contracts or arbitration agreements. Law can be based on many different things, including culture and social custom, family or religious beliefs, and morals.

In most countries there are two types of law – common law and civil law. In a common law country laws are derived from a combination of precedent and the judgments of judges in individual cases, which are then compiled into books called case law. A judge’s decision is considered binding on other judges in the same jurisdiction and, in some cases, other courts within the same jurisdiction if they cite that judgement as an authoritative source.

Civil law, which covers most legal activities and transactions, is based on codes that define rights and obligations. The rules in these codes are compiled by a group of judges who are known as the judiciary. Civil law includes fields such as property, contract, tort, and criminal law. The judiciary also resolves disputes between individuals and determines the guilt or innocence of people who are charged with a crime, such as murder.

The law can also be applied at a global level, for example through treaties and international agreements. These laws set out how countries can interact with each other in areas such as trade, the environment, or military action.

Some of the most important concepts associated with law are equality and fairness. These are incorporated into the constitutions of most countries and reflected in the way that people are treated by the courts and in the general day-to-day activities of society.