Ethnicity is the term for the
culture of peoples in a geographic region.
Ethnicity is being connected by language, heritage,
religion, and customs. To be a member of an ethnic group is to conform to some or all of those practices. etc.
Race is genetics and ethnicity is
culture.
Race and ethnicity can overlap, but they are distinct.
A Japanese-American would be a member of the Japanese or East
Asian race, but, if they
don't practice any of the customs of their ancestors, or have no
knowledge of the Japanese language they might not identify with the ethnicity, and instead consider themselves to be American.