Noun
courtesy title (plural courtesy titles)
A person's title that has no legal validity but is used through custom or courtesy, particularly for children of the nobility.
The death of John Pennington had left his widow in circumstances which were more straitened than ever, and the Park had receded even from her notepaper, where it had long been retained as a courtesy title on the principle that addresses are given to us to conceal our whereabouts. Saki
A prince with the rank of fils de France (Son of France) is surnamed "de France"; all the male-line descendants of each fils de France, however, took his main title (whether an appanage or a courtesy title ) as their family or last name. Source: Internet
However "Docteur" may be used as a courtesy title when speaking to a physician, e.g., "Bonjour Docteur". Source: Internet
The class did not survive the Revolution ; but the courtesy title of abbé, having long lost all connection in people's minds with any special ecclesiastical function, remained as a convenient general term applicable to any clergyman. Source: Internet
The Duke's eldest son's eldest son can use the courtesy title Earl of Sunderland, and the duke's eldest son's eldest son's eldest son (eldest great-grandson) the title Lord Spencer of Wormleighton (not to be confused with Earl Spencer ). Source: Internet
The title of 'Major' was sometimes used by someone who had left the Army as a courtesy title. Source: Internet