Da·ci·a (dā′shē-ə, -shə) An ancient region and Roman province corresponding roughly to modern Romania. Inhabited before the Christian era by a people of Thracian stock with an advanced material culture, the region was abandoned to the Goths after ad 270. Da′ci·an adj. & n. Dacia (ˈdeɪsɪə) n (Placename) an ancient region bounded by the ...