immigration UK /ɪmɪˈɡɹeɪʃn/US /ˌɪmɪˈɡɹeɪʃən/ noun2 •The act of immigrating; the passing or coming into a country of which one is not native born for the purpose of permanent residence. •The process of going through immigration checks at a border checkpoint.It took ages to get through immigration last time. formsimmigrations