Major rivers in Russia and neighbouring countries include the Dniester, Dnieper, Don (and its tributary the Donets). They flow into the Black Sea—the Don doing so via the Sea of Azov.
These names are believed to derive from the Iranic words danu (‘river’). For example, the Dnieper comes from a form reconstructed as *danu para (‘river to the rear’) and Dniester from the form reconstructed as *danu nazdya (‘river to the front’). The same Indo-European root is believed to underlie the Celtic Danuvius (‘Danube’).
Modern river names in some other areas are believed to derive from:
- originally Slavonic names between the upper Vistula basin and the middle Dnieper.
- originally Baltic names in a larger area to the north as far as the Baltic coasts of modern Lithuania and Latvia, from the middle and lower Vistula in the west to the upper Dnieper and upper Volga in the east.
- originally Finno-Ugric names northeast of the areas of originally Baltic river names.
The origins of river names hint at the languages spoken by people living near those rivers those names were established. The Iranic, Celtic, Slavonic and Baltic language groups are all part of the Indo-European family of languages. Finno-Ugric is a separate language family.
In Search of The Indo-Europeans: Language, Archaeology and Myth, JP Mallory (1989)