The name of the Orne in Normandy, which is referred to as the Olinas by Ptolemy,[3] is a homonym of Fluvius Olne, the Orne saosnoise in Sarthe, which Xavier Delamarre traces back to the Celtic olīnā (elbow).
Hydrology and water quality
The waters of the Orne are typically moderately turbid and brown in colour. Its pH level has been measured at 8.5[4] at the town of St. Andre sur Orne where summer water temperatures approximate 18 °C (64 °F). Electrical conductivity of the water has been measured at 30 microsiemens per centimeter.[citation needed]