Vlach Syllabification: (Vlach)Pronunciation: /vläk, vlak/Definition of Vlach noun a member of the indigenous population of Romania and Moldova, claiming descent from the inhabitants of the Roman province of Dacia. adjective relating to the Vlach. Origin:from a Slavic word meaning 'foreigner', from a Germanic word related to Old English Wælisc (see Welsh). Compare with WallachiaVlach in other Oxford dictionaries Definition of Vlach in the British & World English dictionary