"Pertaining to race; peculiar to a race or nation; ethnological. Also, pertaining to or having common racial, cultural, religious, or linguistic characteristics, esp. designating a racial or other group within a larger system"
and
"ethnic minority (group), a group of people differentiated from the rest of the community by racial origins or cultural background, and usu. claiming or enjoying official recognition of their group identity."
(Oxford English Dictionary)
There are various sources of further information & advice:
If you feel you are being discriminated against on the groups of ethnicity please see our harrassment and discrimination pages for advice on action you can take.