Sar·ma·tia (sär-mā'shə, -shē-ə) An ancient region of eastern Europe northeast of the Black Sea. The Sarmatian people occupied the area after the fourth century B.C. and fled across the Carpathian Mountains and along the Danube River after the onslaught of the Huns. The term is also applied to the territory between the Vistula and Volga rivers during the time of the Roman Empire. Sar·ma'tian adj. & n.