In law, custom can be described as the established patterns of behavior that can be objectively verified within a particular social setting. Law is a system of rules enforced through a set of Institutions used as an instrument to underpin civil obedience politics economics and society A claim can be carried out in defense of "what has always been done and accepted by law. " Generally, customary law exists where:
The modern codification of civil law developed out of the customs, or coutumes of the Middle Ages, expressions of law that developed in particular communities and slowly collected and written down by local jurists. In Law, codification is the process of collecting and restating the law of a Jurisdiction in certain areas usually by subject forming a Legal code. Civil law or Romano-Germanic law or Continental law is the predominant system of law in the world. JURIST is an online legal news service hosted by the University of Pittsburgh School of Law, written by founder Professor Bernard Hibbitts and a staff of more than Such customs acquired the force of law when they became the undisputed rule by which certain entitlements (rights) or obligations were regulated between members of a community. A right is a legal or moral Entitlement or Permission. Rights are of vital importance in theories of Justice and deontological ethics An obligation is a requirement to take some course of action whether legal or moral. .
In international law, customary law refers to the Law of Nations or the legal norms that have developed through the customary exchanges between states over time, whether based on diplomacy or aggression. International law is the term commonly used for referring to the system of implicit and explicit agreements that bind together nation-states in adherence to recognized values and standards A state is a political association with effective Sovereignty over a geographic Area and representing a Population. Diplomacy is the art and practice of conducting Negotiations between representatives of groups or states Essentially, legal obligations are believed to arise between states to carry out their affairs consistently with past accepted conduct. These customs can also change based on the acceptance or rejection by states of particular acts. Some principles of customary law have achieved the force of peremptory norms, which cannot be violated or altered except by a norm of comparable strength. A peremptory norm (also called jus cogens or ius cogens, Latin for "compelling law" is a fundamental principle of These norms are said to gain their strength from universal acceptance, such as the prohibitions against genocide and slavery. Genocide is the deliberate and systematic destruction in whole or in part of an ethnic racial religious or national group As a social-economic system slavery is a legal institution under which a Person (called "a slave" is compelled to work for another Customary international law can be distinguished from treaty law, which consists of explicit agreements between nations to assume obligations. A Treaty is an agreement under International law entered into by actors in international law namely States and International organizations. However, many treaties are attempts to codify pre-existing customary law. With this said customary international law is often question as to its validity
Customary law is a recognized, but inferior source of law, within jurisdictions of the civil law tradition. Civil law or Romano-Germanic law or Continental law is the predominant system of law in the world. It is strictly inferior to both statutes and regulations. A statute is a formal written enactment of a Legislative authority that governs a Country, State, City, or County. This article is for the legal term For regulation of genes see Regulation of gene expression. In addressing custom as a source of law within the civil law tradition, John Henry Merryman notes that, though the attention it is given in scholarly works is great, its importance is "slight and decreasing. "
In the Scandinavian countries customary law continues to exist and has great influence. Terminology and usage As a cultural term "Scandinavia" has no official definition and is subject to usage by those who identify with the culture in question as well Customary law is also used in some Third World countries, such as in Africa, usually used alongside common or civil law. Third World is a name given to nations that are generally considered to be underdeveloped economically 
Custom is used in tort law to help determine negligence. Tort law is the name given to a body of law that creates and provides remedies for civil wrongs that do not arise out of Contractual duties Negligence (Lat negligentia from negligere to neglect literally "not to pick up" is a legal concept in the Common law legal systems usually used to Following or disregarding a custom is not determinative of negligence, but instead is an indication of possible best practices or alternatives to a particular action. The case R v Boomsdale defines this principle with the courts ruling that Mr Boomsdale customry practice was not sufficient to be deemed an act of negligence