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.
Brigach
Shortly thereafter, the Brigach leaves the Black Forest behind, about halfway along its course, and enters the much flatter Baar region near Villingen, which is dominated by open countryside, with larger settlements than in its upper reaches. In the middle of the town, it changes direction to the south and receives a number of tributaries from the north, of which two are from the Black Forest to the west and are more than 10 kilometres long: the "Warenbach", whose confluence is in the borough of Villingen, and the "Holenbach" whose confluence is in the next municipality of Brigachtal. Below the village of Klengen, the Brigach passes over the boundary of the district into the borough of Donaueschingen. Once again, the valley passes through wooded hills, the river develops meanders and then swings left on an easterly course through the urban part of the borough. In the left-hand part of the castle park, a karst spring, which has been regarded as a source of the Danube for centuries and whose upper reaches are called the "Donaubach" ("Danube Stream") is routed underground through the park into the Brigach. Its confluence is marked by a temple dedicated to the former German Emperor, Kaiser William II. Compared with its two headstreams, this source of the Danube is, however, hydrologically insignificant. A mile and a half east of the "Donaubach" spring, the Brigach unites with the Breg, a river which joins from the right and originates in the High Black Forest, to form the River Danube.