tiara

An ornamental, often jeweled, crownlike semicircle worn on the head by women on formal occasions.

The triple crown historically worn by the pope, especially at his coronation ceremony, and still used heraldically as a symbol of the papacy.

An ornament or article of dress with which the ancient Persians covered the head: a kind of turban.

A cylindrical diadem pointed at the top, tipped with the mound and cross of sovereignty, and surrounded with three crowns, which the Pope wears as a symbol of his threefold sovereignty.

Figuratively, the papal dignity.