Voidomatis is a river in the Ioannina regional unit in northwestern Greece, and is a tributary of the Aoös river. The main current sources are located under the village of Vikos. Along its path it converges with other water currents originating from the banks of Tymfi or the Vikos Gorge it ends close to Konitsa. The river has a total length of 15 kilometers. The name Voidomatis,(meaning: the eye of the ox), derives from the fact that oxes have clear blue eyes, like the waters of this river. Also, there is the Slavic etymology: Bode–Mat which means "good water".