Someone's ethnicity refers to their cultural or national background. It can also refer to the culture and society that they associate with. Ethnicity consists of learned cultural traits, making it different than race, which is biological. Some of these cultural traits include religion, clothing, language and traditions.
People of the same ethnicity belong to the same ethnic group, which can be as large as millions of people across the world or as small as a few dozen people from one specific area. Members of these groups might not necessarily share the same racial background, but they all identify with the same culture.