The paper discusses the meaning and significance of ethnicity, with emphasis on the political role of ethnicity in groups. Information is presented from a review of literature regarding groups from four viewpoints--subjective/behavioral strategies, social science research, ethnographic interpretations, and the culture-population-group frame of reference. All literature is evaluated according to four levels of abstraction for the insights it contributes to an understanding of ethnicity. Levels of abstraction are commonsense perceptions, interpretations of behavior, ethnographic interpretations, and sociological interpretations. General findings derived from these various research approaches indicate that ethnic factors are operative with respect to individuals, population aggregates, and corporately organized groups; inter-ethnic relations between individuals are different from those among groups; ethnic identities influence competitive advantage and/or disadvantage when resources are limited; and all ethnic groups are in competition to monopolize key resources within the overall political economy. (DB)