Wikipedia
Arausio (god)
Arausio was a local Celtic water god who gave his name to the town of Arausio ( Orange) in southern Gaul, as attested to by ancient inscriptions.
The modern name of both the city and the family that established itself there, the House of Orange-Nassau, is a corrupted version of Celtic word Arausio. In the Middle Ages the name of the city was conflated in French and Late Latin with another word, orange.