A hyphenated ethnicity or hyphenated identity is a reference to an ethnicity combined with the name of the country of residence. The term is an extension of the term "hyphenated American". The term refers to the use of a hyphen between the name of an ethnicity and the name of the country in compound nouns: Irish-American, etc., although modern English language style guides recommend dropping the hyphen: "Irish American".
The concept should not be confused with that of mixed ethnicity and multiraciality, i.e., the ethnicity or race of a person whose parents have different ethnicities/races, which can also be written in a hyphenated way.
The term "hyphenated American" originated in 1890s and was used disparagingly as a reference to immigrants who, by brandishing their ethnic origin, allegedly demonstrated an incomplete allegiance to the United States, especially during the World War I period.
Jeffrey Lesser wrote: "While there is no linguistic categories that acknowledge hyphenated ethnicity (a third generation Brazilian of Japanese descendant remains 'Japanese' while a fourth-generation Brazilian of Lebanese descent may become a turco, an arabe, a sirio, or a sirio-libanese), in fact immigrant communities aggressively tried to negotiate a status that allowed for both Brazilian nationality and ethnic difference". 
- Visconti, L., Jafari, A., Batat, W., Broeckerhoff, A., Dedeoglu, A., Demangeot, C., ... Weinberger, M. F. (2014). "Consumer ethnicity three decades after: A TCR agenda", Journal of Marketing Management, 30, 1882-1922. (online)
- John Higham, Strangers in the Land: Patterns of American Nativism, 1860–1925 (1955) p. 198
- Jeffrey Lesser, "(Re) Creating Ethnicity: Middle Eastern Immigration to Brazil", The Americas Vol. 53, No. 1 (Jul., 1996), pp. 45-65 JSTOR 1007473