Meaning of “naturalize” - Learner’s Dictionary

naturalize

verb us uk /ˈnætʃərəlaɪz/
be naturalized

to officially become a member of another country:

a naturalized US citizen
naturalization noun [ U ] us uk /ˌnætʃərəlaɪˈzeɪʃən/

(Definition of “naturalize” from the Cambridge Learner’s Dictionary © Cambridge University Press)