seg·re·ga·tion /ˌse-gri-'gā-shən/ n
1: separation of individuals or groups and esp. racial groups compare desegregation
de facto segregation: segregation of racial groups that arises as a result of economic, social, or other factors rather than by operation or enforcement of laws or other official state action
de jure segregation: segregation intended or mandated by law or otherwise intentionally arising from state action
◇ De jure segregation is illegal.
2: separate confinement of prisoners within a penal institution
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.