a. Of, relating to, or characteristic of a sizable group of people sharing a common and distinctive racial, national, religious, linguistic, or cultural heritage.
b. Being a member of a particular ethnic group, especially belonging to a national group by heritage or culture but residing outside its national boundaries: ethnic Hungarians living in northern Serbia.
2. Relating to a people not Christian or Jewish.
A member of a particular ethnic group, especially one who maintains the language or customs of the group.
[Middle English, heathen, from Late Latin ethnicus, from Greek ethnikos, from ethnos, people, nation; see s(w)e- in Indo-European roots.]
Word History: When it is said in a Middle English text written before 1400 that a part of a temple fell down and mad a gret distruccione of ethnykis, one wonders why ethnics were singled out for death. The word ethnic in this context, however, means gentile, coming as it does from the Greek adjective ethnikos, meaning national, foreign, gentile. The adjective is derived from the noun ethnos, people, nation, foreign people, that in the plural phrase ta ethn meant foreign nations. In translating the Hebrew Scriptures into Greek, this phrase was used for Hebrew gym, gentiles; hence the sense of the noun in the Middle English quotation. The noun ethnic in this sense or the related sense heathen is not recorded after 1728, although the related adjective sense is still used. But probably under the influence of other words going back to Greek ethnos, such as ethnography and ethnology, the adjective ethnic broadened in meaning in the 19th century. After this broadening the noun sense a member of a particular ethnic group, first recorded in 1945, came into existence.
ethnic /nk/ adj. related to group characteristics, such as race, country of origin, religion, or culture: The ethnic makeup of the USA is incredibly varied.-n. [C;U] ethnicity /nsti/.