the.com/ethnicity

means A shared identity based on ancestry, culture, language, or nationality that a group recognizes in itself.

from From Greek 'ethnos,' meaning a people, nation, or group living together — originally used by Greeks to describe other nations and tribes (often the 'non-Greek' ones), which tells you something about who gets to name and who gets named. 'Ethnic' entered English centuries ago in that same outsider-looking-in sense, meaning 'heathen' or 'pagan.' Only later did it soften into the neutral, descriptive 'ethnicity' we use now — a word with a long history of being applied to others before anyone used it to describe themselves.