Not sure if my homeland Northern Ireland is good example for defining ethnicity. I've rarely heard anyone talk about our "two communities" as ethnic groups, and

Not sure if my homeland Northern Ireland is good example for defining ethnicity. I've rarely heard anyone talk about our "two communities" as ethnic groups, and even your own descriptions are political (Unionist/Nationalist) and religious (Protestant/Catholic). Ethnicity is not a clearly defined term and in a "post-conflict" place like Northern Ireland, I think we intentionally avoid terminology which can encourage a sense of division. It also suffers from the same deficiency as the word "race" when it comes to mixing. Even if we can say that this community predominantly came from English and Scottish settlers and this community predominantly came from "native" Irish, how many people today can say that they only have ancestors from one of those two?