1. any of the fixed hereditary classes of the Hindu caste system, which are held to be distinguished by different levels of essential purity. The main classes are (in order of status) brahmins or priests, warriors, merchants, and laborers; outcastes or untouchables are people of no caste. Until recently, mobility or intermarriage between castes was exceptional. See also fixed class society; Hinduism; social immobility.

2. any system of social stratification regarded as being comparably rigid.

3. any class of society distinguished by inherited privilege and exclusivity.