Tiara

Definition:

(n.) 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.
(n.) 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.

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taira vs. tiara