Bačka (Serbian: Бачка/Bačka, pronounced [bâːt͡ʃkaː]; Hungarian: Bácska, pronounced [ˈbaːt͡ʃkɒ]) is a geographical and historical area within the Pannonian Plain bordered by the river Danube to the west and south, and by the river Tisza to the east. It is divided between Serbia and Hungary. Most of the area is located within the Vojvodina region in Serbia and Novi Sad, the capital of Vojvodina, lies on the border between Bačka and Syrmia. The smaller northern part of the geographical area is located within Bács-Kiskun County, in Hungary.
The name of the region in Serbian is Bačka or Бачка and in Hungarian is Bácska. In other languages of the region, the name is similar: Bačka in Croatian and Bunjevac, Báčka in Slovak, Бачка (Bačka) in Rusyn, and Batschka in German.
According to Serbian historians, Bačka is a typical Slavic name form, created from "Bač" (name of historical town in Bačka) and suffix "ka" (which designating "the land that belong to Bač"). There are many other similar name forms used in Serbian and other Slavic languages, for example Šajkaška, Srpska, Hrvatska (Croatia), Timočka Krajina, Bugarska (Bulgaria), Polska (Poland), etc.