What is "ub"

init. 1 (label en historical) The Urząd Bezpieczeństwa, a branch of the secret police in communist Poland. 2 (label en computer programming C C++) Undefined behavior; behavior not defined in the language standard.

UB may refer to:

The Ub ( Serbian Cyrillic: Уб) is a river in western Serbia, a 57 km-long right and longest tributary to Tamnava river.

The Ub originates from the Vlašić mountain in Podgorina region of west Serbia, near the village of Kasapo. From its source to the mouth, the river flows to the east, parallel to the river Tamnava, which it will eventually join.

The villages located in the upper section of the river's flow are Družetić, Pambukovica and Čučuge, where the Ub slightly turns to the north, passes through the villages of Tvrdojevac and Zvizdar, and the small town of Ub, named after the river.

The Ub continues to the north and meets the Tamnava river near the village of Šarbane. The river drains an area of 274 km², belongs to the Black Sea drainage basin and it is not navigable.