A person's "ethnicity" refers to their ethnic background, which means which group of people their ancestors belonged to.

Here are some examples of different ethnicities:

• Irish
• Korean
• Native American
• Jewish
• French Canadian
• Persian

"Ethnicity" is a little different from "nationality", which is just the country that a person is from:

• American
• Russian
• Indian

...and "race", which describes a few major groups of people based mostly on skin color:

• white
• black
• Asian

The word "ethnicity" sounds kind of formal and scientific. It's usually more polite to talk about people's "ethnicity" than their "race".