naturalisation (Noun) — The quality of being brought into conformity with nature.
naturalisation (Noun) — (law) the proceeding whereby a foreigner is granted citizenship.
naturalisation (Noun) — The introduction of animals or plants to places where they flourish but are not indigenous.
naturalisation (Noun) — Changing the pronunciation of a borrowed word to agree with the borrowers' phonology. ex. "the naturalisation in English of many Italian words"