The story
Anglicized spelling of the Aboriginal word kouranbong, meaning either "water over rocks" or "rocky bottom creek." The word has changed spelling over the years from its original spelling of Kuringbong (1834) to Coorumbung (1841) and Corumbong (1879). In the year of 1866 the word was officially adopted by Cooranbong, New South Wales and its current spelling was secured.
Etymology from Wiktionary, CC BY-SA 4.0.