“A caste system is an artificial construction, a fixed and embedded ranking of human value that sets the presumed supremacy of one group against the presumed inferiority of other groups on the basis of ancestry and often immutable traits, traits that would be neutral in the abstract but are ascribed life-and-death meaning in a hierarchy favoring the dominant caste whose forebears designed it. A caste system uses rigid, often arbitrary boundaries to keep the ranked groupings apart, distinct from one another and in their assigned places.”

Caste by Isabel Wilkerson