| a historic region in S France, on the border of Spain and the Mediterranean Sea. |
Rous·sil·lon  (rōō-sē-yôɴ') A historical region of southern France bordering on Spain and the Mediterranean Sea. Originally inhabited by Iberians, it became part of Roman Gaul after c. 121 B.C. and later changed hands many times, eventually becoming a Spanish possession that was transferred to France by the Treaty of the Pyrenees (1659). |
siˈyoʊn