Final answer:
An ethnic boundary marker is a symbol or characteristic that distinguishes one ethnic group from another. It helps to define and maintain ethnic identities and demarcate boundaries between different ethnic groups.
Step-by-step explanation:
An ethnic boundary marker is a symbol or characteristic that distinguishes one ethnic group from another. It can be a physical, social, cultural, or linguistic feature that separates different ethnic groups. For example, in the United States, the terms African-American and Asian-American are ethnic boundary markers that indicate an individual's African or Asian ancestry.
The purpose of an ethnic boundary marker is to emphasize and maintain the identities of different ethnic groups. It helps individuals and societies to define and recognize their own ethnic identities, as well as to demarcate the boundaries between different ethnic groups. Ethnic boundary markers also play a role in the social, cultural, and political interactions among diverse ethnic groups.