Word History: Across Europe, from Russia to England, there are rivers with names beginning with a d and also containing an n: the Don, the Dnieper, and the Dniester of Russia and Ukraine, the Danube of central Europe, and the six rivers called Don in Britain. All of these names come from the Proto-Indo-European word *dānu-, meaning "river" and derived from the root *dā- "to flow, flowing." In Avestan, the earliest Iranian language we know, dānu- means "river, stream." In modern Ossetic (the language of the Ossets, descendants of the Scythians, an Iranian tribe of the Russian steppes), don means "river, stream." This word appears in the name of the Don River of Russia. Dnieper and Dniester (earlier Danapris and Danastius, respectively) come from Scythian Dānu apara and Dānu nazdya ("the river in the rear" and "the river in front," respectively). The name of the six rivers called Don in Britain comes from the Celtic version of the "river" word, also *dānu-. This Celtic word survives more or less intact in the name of the Danube, which was called Dānuvius by the Romans. The presence of Celtic river names both in central Europe and in Britain attests to the Celts' earlier glory, and recalls a time when Celtic languages were spoken across Europe from the valley of the Danube in the east to Spain and Ireland in the west.