Dauphin was the hereditary title of the heir to the throne of France - the equivalent of 'Prince of Wales in Britain - between 1349 and 1830, until the Republic was established in France after 1789. The title is sometimes spelled 'dolphin' in archaic English: this reflects its ultimate origin.
The wife of the Dauphin is called the Dauphine (note that the title bears no accent - unlike the region), sometimes rendered in English as Dauphiness. The words dauphinois (masculine) and dauphinoise (feminine) are adjectives meaning 'of, or connected to, the Dauphiné; as nouns, they mean 'inhabitant of the Dauphiné.
- Etymological/historical note: the title Dauphin was first used by the rulers of the Dauphiné, a region of France in the south-east, centred on Grenoble. It became a province when its ruler, Humbert III, who was titled Dauphin of Viennois (Vienne is a neighbouring area, of which he was also count) sold the Dauphiné to Philip of Valois in 1349 in order to meet his debts, on condition (amongst others) that the title be always borne by the heir apparent to the kingdom. The title of dauphin was not unique to Viennois, or the Dauphiné; it was also borne by the lords of Auvergne and others. Its origin is lost in the past; it may have been a nickname at some stage. The connection with the marine mammal (a small whale, Delphinus Delphis) is found in original Latin documents; according to Littré's Dictionary, the name was first used by the lords of the province as their coat of arms was three dolphins. Dauphiné was named after the lords. As a regular system of heraldry seems not to have developed before the twelfth century, this may not be the case; but there is a connection between the mammal and the title.