New High German
The river's name was recorded around 830 as "Obacra" and, later, as "Ovokare" und "Ovakara". The origin of the name is derived from the roots "ov-" and "-akara" meaning “upper” (cf. New High German "ober-") and “onward rushing” (rendered in German as “Vorwärtsdrängende”) as distinct from its tributary, the Ecker, whose name means only “onward rushing”.