RUC, THE Meaning of RUC, THE in English RUC, the /ˌɑː juː ˈsiː $ ˌɑːr-/ BrE AmE abbreviation for Royal Ulster Constabulary; the former name of the PSNI (Police Service of Northern ireland) Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012