dauphin
noun /ˈdəʊfæ̃/, /ˈdəʊfæn/
/ˈdəʊfæ̃/, /ˈdəʊfæn/
(old use)- the oldest son of the king of FranceWord OriginFrench, from the family name of the lords of the Dauphiné, an area of SE France: ultimately a nickname meaning ‘dolphin’. In 1349 the future Charles V acquired the lands and the title; when king he ceded them to his eldest son, establishing the practice of passing both title and lands to the Crown prince.