A system of inherited social ranking in which a person's place in the hierarchy is fixed at birth, transmitted through descent, and enforced by rules of endogamy, occupational segregation, ritual purity, and graduated rights and degradations. The paradigmatic case is the varna/jati system of South Asia, formally outlawed in independent India but in practice still structuring Indian social life in many ways. The term has been extended analytically — controversially but with growing acceptance — to other inherited rank systems: Nazi racial law, the Buraku of Japan, and (in the work of Oliver Cromwell Cox, Gunnar Myrdal, and most recently Isabel Wilkerson) American racial hierarchy.
The argument that the American racial order is best understood as a caste system, rather than as racism considered as prejudice or as the legacy of slavery considered as a wound, runs back at least to the 1940s — Myrdal's An American Dilemma (1944) used it; Cox's Caste, Class, and Race (1948) argued against it. Wilkerson's Caste (2020) brought the framework to wide American attention, setting out eight "pillars" — divine or natural justification, heritability, endogamy, purity vs. pollution, occupational hierarchy, dehumanization, terror, and inherent superiority/inferiority — that she argued operate across the Indian, Nazi, and American cases.
The use is contested. Some scholars argue that caste obscures the specific dynamics of Racism — particularly the histories of slavery and settler colonialism that racism foregrounds — and that the analogy to South Asia is loose. Defenders argue that the analytic gain is precisely in shifting attention from prejudice and attitudes to the inherited ranking that survives shifts in stated ideology. The contemporary American conversation now includes caste as one of several available framings, alongside racism, white supremacy, and racial capitalism, each illuminating something the others underemphasize.