ethnogenesis

English Wikipedia has an article on:

ethnogenesis

Wikipedia

From ethno- +‎ -genesis. While attested incidentally before the twentieth century, it gained currency particularly in the postwar era as a scholarly concept.

ethnogenesis (countable and uncountable, plural ethnogeneses)

2. The emergence of a distinct, recognizable, ethnic identity.

• ethnogenetic
• ethnogeny

• “ethnogenesis”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.