A dynamic set of historically derived and institutionalized ideas and practices that (1) sorts people into ethnic groups according to perceived physical and behavioral human characteristics; (2) associates differential value, power and privilege with these characteristics and establishes a social status ranking among the different groups; and (3)emerges (a) when groups are perceived to pose a threat (political, economic or cultural) to each other’s world view or way of life; and/or (b) to justify the denigration and exploitation (past, current or future) of, and prejudice toward, other groups.

Markus, H. R. (2008). Pride, prejudice, and ambivalence: Toward a unified theory of race and ethnicity. American Psychologist, 63(8), pp.651-70.