noun the pope's triple crown. it was at first a round, high cap, but was afterward encompassed with a crown, subsequently with a second, and finally with a third. fig.: the papal dignity.
2. tiara ·noun a form of headdress worn by the ancient persians. according to xenophon, the royal tiara was encircled with a diadem, and was high and erect, while those of the people were flexible, or had rims turned over.