A dynamic set of historically derived and institutionalized ideas and practices that (1) allows people to identify or to be identified with groupings of people based on presumed (and usually claimed) commonalities including language, history, nation or region of origin, customs, ways of being, religion, names, physical appearance and/or genealogy or ancestry; (2) can be a source of meaning, action and identity; and(3) confers a sense of belonging, pride and motivation.

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