1. the process by which people belonging to an ethnic minority tend to lose, alter, or redefine their sense of ethnic identity over time, generally as a result of assimilation with the dominant culture, intermarriage, or loss of contact with their culture of origin. See also cultural drift.

2. the tendency for people of the same ethnicity to gather in or be assigned to the same formal or informal groups, whether as a result of voluntary association or the policies of others. At work, for example, people of the same ethnicity are often assigned to the same work team or supervisor.