The Or river [ɔ:] (Modern Arithide [œ:], Classical Arithide [ɔr]) originates in the central Iryagi, and follows the Iryagi foothills closely first southwest then southeast into Erdia before emptying into the Chisthian Sea through a triangular delta.
The name of the Or derives ultimately from Proto-Arophanic *uora, meaning, simply, river. From the same root also arose the modern word for "river", ores, as well as the names of the Yos, Jedi, Varant and Ous rivers.
Historical course shifts
Due to the softness of the alluvial plain (partially the work of the Or's own rich mineral deposits) through which the lower Or flows, course shifts brought about by the sheer erosive power of its discharge have been very common throughout history, and are well documented by historians due to their magnitude and impact. While continually replenishing the mineral stock of the plain and assuring continued fertility, the swings of the river have proven disastrous for settlement, most recently, in 1992 CIE, almost severing the water supply to the city of Kyris at its mouth. Historically, a shift in the course of the Or is believed to have resulted in the flooding of the Erda settlements sometime after the Southerly Movement, triggering the flight to the telefluvial areas of the Nuroi, Pisa and Duvai cultures.