Segregation or discriminatory practices that occur even when there is no explicit legal enforcement, such as school segregation in much of the united states today, is called segregation

The answer is de facto segregation. Racial isolation, particularly in state-funded schools, that happens "by certainty" instead of by legitimate prerequisite. For instance, regularly the grouping of African-Americans in specific neighborhoods produces neighborhood schools that are overwhelmingly dark or isolated in truth ( true ), in spite of the fact that not by law ( by right ).