IPA: /ˌnætʃərəlɪˈzeɪʃən/
KK: /ˈnætʃərəlɪˌzeɪʃən/
The process of becoming a citizen of a country after meeting certain requirements, or the act of making something natural or accepted in a new environment.
After living in the country for several years, she completed her naturalization and became a citizen.
Naturalization → It is formed from "natural" (from Latin *naturalis*, meaning of nature) and "-ization" (meaning the process of making or becoming). The word "naturalization" refers to the process of making someone a citizen, as if they are being made a part of the natural order of a country.
Think of the process of becoming part of the 'natural' order of a country — 'natural' relates to nature, and '-ization' indicates a process.