De jure (in Classical Latin de iure) is an expression that means "of law", as contrasted with de facto, which means "in fact". Classical Latin is the form of the Latin language used by the ancient Romans in what is usually regarded as "classical" Latin literature. Law is a system of rules enforced through a set of Institutions used as an instrument to underpin civil obedience politics economics and society
The terms de jure and de facto are used instead of "in principle" and "in practice", respectively, when one is describing political or legal situations. Politics Politics is the process by which groups of people make decisions
In a legal context, de jure is also translated as "by law". A practice may exist de facto, where for example the people obey a contract as though there were a law enforcing it yet there is no such law. A process known as "desuetude" may allow de facto practices to replace obsolete laws. In Law, desuetude (from the Latin word desuetudo outdated no longer custom is a doctrine that causes Statutes similar legislation or legal principles to lapse and On the other hand, practices may exist de jure and not be obeyed or observed by the people.
As a logical complement of "de facto", where "de facto" has a more generic acceptance (not so restrictive as at legal context), like in social sciences. In Discrete mathematics and predominantly in Set theory, a complement is a concept used in comparisons of sets to refer to the unique values of one set in relation The social sciences comprise academic disciplines concerned with the study of the social life of human groups and individuals including Anthropology, Communication studies See de facto standards and other usages. A de facto standard is a Standard (formal or informal that has achieved a dominant and accepted position