Heir Apparent of the French Royal Family

Puzzle 6 of Making Sushi Pack

Question is: Heir Apparent of the French Royal Family

and the answer is: DAUPHIN

Word Meaning:

DAUPHIN — The eldest son of the king of France. Under the Valois and Bourbon dynasties, the Dauphin of France, generally shortened to Dauphin, was heir apparent to the throne of France. The title derived from the main title of the Dauphin, Dauphin of Viennois.

Definitions from Wiktionary.