Danube
"Danube" is an Old European river name derived from a Proto-Indo-European "*dānu". Other river names from the same root include the Dunaj, Dzvina/Daugava, Don, Donets, Dnieper, Dniestr, Dysna, Tana and Tuoni. In Rigvedic Sanskrit, "dānu" means "fluid, drop", in Avestan, the same word means "river". In the Rigveda, "Dānu" once appears as the mother of Vrtra, "a dragon blocking the course of the rivers." The Finnish word for Danube is Tonava, which is most likely derived from the word for the river in Swedish and German, "Donau". Its Sámi name "Deatnu" means "Great River". It is possible that "dānu" in Scythian as in Avestan was a generic word for "river": "Dnieper" and "Dniestr", from "Danapris" and "Danastius", are presumed to continue Scythian "*dānu apara" "far river" and "*dānu nazdya-" "near river", respectively.
Danube Vilayet
The vilayet was created from the northern parts of Silistra Province along the Danube River and eyalets of Niš, Vidin and Silistra. This vilayet was meant to become a model province, showcasing all the progress achieved by the Porte through the modernising Tanzimat reforms. Other vilayets modelled on the vilayet of the Danube were ultimately established throughout the empire by 1876, with the exception of the Arabian peninsula and the by then semi-independent Egypt. Rusçuk, today Ruse in Bulgaria, was chosen as the capital of the vilayet due to its position as a key Ottoman port on the Danube.