The Word For Today Is ‘Ethnogenesis’

Wikipedia: Ethnogenesis (from Greek ethnos ἔθνος, “group of people, nation”, and genesis γένεσις, “beginning, coming into being”; plural ethnogeneses) is a process in which a group of people acquire an ethnicity, that is, a group identity that identifies them as an ethnic group. This can originate through a process of self-identification as well as come about as the result of outside identification.