assimilation

US /əˌsɪm.əˈleɪ.ʃən/
UK /əˌsɪm.əˈleɪ.ʃən/
1.

sự đồng hóa

the process of becoming a part, or making someone become a part, of a group, country, society, etc.:

:
The assimilation of ethnic Germans in the U.S. was accelerated by the two world wars.