From a Norman French name, Raulf, a contracted form of the Germanic personal name Radulf, derived from rād ‘counsel’ + wulf ‘wolf’. The spelling with -ph is due to classical influence in the 18th century.
English and Welsh: patronymic from the Middle English personal name Jon(e) (see John). The surname is especially common in Wales and southern central England. In North America this name has absorbed various cognate and like-sounding surnames from other languages. (For forms, see Hanks and Hodges 1988).