Unlike race, which is based largely on physical attributes, your ethnicity is based on traditions, language, nationality or cultural heritage. When you think of your ethnicity, you look beyond your physical characteristics to traits that you share with the culture around you.
While race might be derived from the color of your skin, ethnicity takes into account your cultural construct. For example, you might have a German ethnicity because your great grandmother or grandfather came from Germany, you speak the language, and you follow German cultural traditions (www.yourdictionary.com)