Definition of Neisse
- 1a river in central Europe that rises in the north of the Czech Republic and flows over 140 miles (225 km) north, forming the southern part of the border between Germany and Poland (the Oder-Neisse Line) and joining the Oder River northeast of Cottbus. German name Lausitzer Neisse; Polish name Nysa.
- 2a river in southern Poland that rises near the border with the Czech Republic and flows 120 miles (195 km) northeast, through the town of Nysa, and joins the Oder River southeast of Wrocław. German name Glatzer Neisse.