The term Dauphin refers to the title given to the heir apparent of the French throne. The three crossword solutions for this term are SON (3 letters), REINE (5 letters), and NON (3 letters). The solution SON refers to the fact that the Dauphin is the SON of the reigning monarch, while REINE indicates that the Dauphin is the husband of the Queen. Finally, NON indicates that the Dauphin is not the reigning monarch.