High Quality Content by WIKIPEDIA articles! The biretta (Latin: biretum, birretum) is a square cap with three or four peaks or horns, sometimes surmounted by a tuft. Traditionally the three peaked biretta is worn by Roman Catholic clergy and some Anglican and Lutheran clergy. The four peaked biretta is worn as academic dress by those holding a doctoral degree from a pontifical faculty or pontifical university. Occasionally the biretta is worn by advocates in law courts, for instance the Advocates in the Channel Islands.