The concept of caste has undergone a thorough re-examination by social scientists in the past three decades. The result has been a redefinition of caste and the application of the term \u27caste\u27 to social situations found outside the Indian subcontinent. A review of some of the varieties of caste reported in Japan, Africa, Tibet, Korea and North America are outlined and brief historical summaries illustrate the differing conditions under which these systems arose. Utilizing a broad definition of caste, the structural components and concomitants of castes are compared using the features of birth-ascription, endogamy, ritual pollution and traditional occupation. These four criteria are structurally significant in the cross-cultural study of caste-like hierarchies
