Osijek (ôsijeːk) is the fourth-largest city in Croatia, with a population of 96,848 in 2021. It is the largest city and the economic and cultural centre of the eastern Croatian region of Slavonia, as well as the administrative centre of Osijek-Baranja County. Osijek is on the right bank of the Drava River, upstream of its confluence with the Danube, at an elevation of .
The name was given to the city due to its position on elevated ground, which prevented the city being flooded by the local swamp waters. Its name "Osijek" derives from the Croatian word oseka, which means "ebb tide". Due to its history within the Habsburg monarchy and briefly in the Ottoman Empire, as well as the presence of German, Hungarian, and Serbian minorities throughout its history, Osijek has (or had) its names in other languages - Hungarian: Eszék, Essek, Esseg or Essegg, Essek, Ösek, Esgek.
Its ancient name was Mursa and is supposed to come from the Proto-Indo-European