Old European hydronymy

Old European (alteuropäisch) is the term used by Hans Krahe (1964) for the language of the oldest reconstructed stratum of European hydronymy (river names) in Central and Western Europe. The character of these river names is pre-Germanic and pre-Celtic and dated by Krahe to the 2nd millennium BC.

Old European river names are found in the Baltic and southern Scandinavia, in Central Europe, France, the British Isles, and the Iberian and Italian peninsulas. This area is associated with the spread of the later "Western" Indo-European dialects, the Celtic, Italic, Germanic, Baltic and Illyrian branches. Notably exempt are the Balkans and Greece, as well as the Eastern European parts associated with Slavic settlement.

Krahe locates the geographical nucleus of this area as stretching from the Baltic across Western Poland and Germany to the Swiss plateau and the upper Danube north of the Alps, while he considers the Old European river names of southern France, Italy and Spain to be later imports, replacing  "Aegean-Pelasgian" and Iberian substrates  (p. 81), corresponding to Italic, Celtic and Illyrian "invasions" from about 1300 BC.

German linguist Theo Vennemann has suggested that the language of the old European hydronyms was agglutinative and preindoeuropean.

Dur
Dur, a preceltic linguistic root meaning 'water, stream'.
 * the Adur (United Kingdom),
 * the Dour, Kent, Latin Dubris (United Kingdom)
 * the Dore (France),
 * the Doron (France),
 * the Dordogne < Durānius (France),
 * the Douro (Portugal and Spain (known as Douro in portuguese and Duero in spanish)),
 * the Dronne (France),
 * the Dropt < Roman Drotius (France),
 * the Drave and probably the Drac (France),
 * the Drava (Italy, Austria (known as Drau), Slovenia, Croatia, Hungary)
 * the Drawa (Poland),
 * the Durance (France),
 * the Durenque, tributary of the Agout (France)
 * the Eder, tributary of the Fulda (Germany)
 * the Oder (Germany and Poland)