A law is a rule that a country or organization establishes and enforces to regulate its citizens’ behavior. The word is often used to refer specifically to laws about a crime, such as murder; or more generally, to the entire set of rules established by a government, including criminal laws, civil rights and regulations, administrative policies, and procedures. Governments impose laws to keep the peace, maintain the status quo, and resolve disputes. They also protect individuals’ liberties and rights, particularly minorities against majorities; and they foster social justice by ensuring that people are treated fairly. The law serves many other purposes, but these four are central to any society.
Legal systems vary widely across the world. Some nations are ruled by authoritarian governments that maintain order and stability, but may oppress the interests of minorities or political opponents. These governments are sometimes backed by military force, and some have a history of brutally crushing rebellions.
Other countries are governed by constitutional democracies with independent judiciaries that protect the rights of the individual. In these countries, laws are often written by legislatures, and judicial decisions can affect future case law.
The word is also frequently used to describe a system of rules for an activity or situation, such as the sports rules of football or the operating instructions for an airplane. These rules are sometimes called “rules of the game,” and they are meant to create fair play and prevent cheating or violence.
A law can be a statute, an executive order, or a court decision. The word can also mean the governing document for a body, such as a constitution or charter. In the United States, a law can also refer to a bill or act passed by Congress that has been approved by both houses of the U.S. Congress, and signed by the President of the United States to become a law.
Law is a complex and varied field that can include topics as diverse as contract law, family law, and criminal law. For example, contract law regulates agreements that involve money or other property. Property law defines people’s rights and duties toward tangible property (such as land or buildings), and intangible property (such as bank accounts and stocks).
A law can also refer to a scientific statement that describes the invariable relationships between things under specific conditions. For example, Boyle’s law describes the relationship between the pressure and volume of an ideal gas as its temperature changes. The law can also refer to a court decision, such as the conviction of a defendant for a crime. A decision can also be appealed, which is a request to another court to review the decision. The party that requests an appeal is known as the appellant. Appeals can be overturned or upheld. They can also result in a new trial or change the way a case is decided. For example, if a court decides that the evidence presented in a case was flawed or biased, it can change the way it will consider other cases.