6 letters · 9 points in Scrabble
origin# For the river in South Yorkshire: Probably 'the chief river', from Middle English Roder, from Proto-Brythonic *ro + Old Welsh *duβr. # For the river in West Sussex: Back-formation from Rotherbridge. # For the river in East Sussex: Back-formation from Rotherfield. Replaced Middle English Liminel, which is cognate with River Limden.
Etymology from Wiktionary, CC BY-SA 3.0