Law is a system of practices, rules and customs that form a framework to ensure a peaceful society. It is enforced by a controlling authority and sanctions can be imposed when rules are broken. Law can be divided into many different fields including civil law, criminal law and administrative law. It is also a broad term for the legal profession which involves advising people about the law and representing them in court.

It can be difficult to define law as it varies between cultures and nations, but most laws are intended to keep members of society within certain parameters. This includes preventing crime and ensuring that there is fair treatment of all people regardless of their wealth or social class. Some countries have a constitution written down or implicitly understood, which acts as a foundation for the law and guarantees core human and procedural rights to citizens.

Other types of law include labour law, which concerns a tripartite relationship between worker, employer and trade union. Environmental law addresses concerns about air pollution and other environmental issues. Aviation law is regulated by national civil aviation laws which are often aligned with recommendations or mandatory standards set by the International Civil Aviation Organisation or ICAO. Family law refers to the rights and responsibilities of couples and their children. Lastly, constitutional law is the study of how the different branches of government, legislative, executive and judicial, interact with each other. This is sometimes known as separation of powers and is an important feature of a democracy.