A square cornered cloth hat
A Canterbury Cap is a square, four cornered cloth hat which originated in the Catholic Church during the Medieval times. Today it is commonly found in the Anglican Communion and the Catholic Church, being used by some Ordinariate clergy. It is also soft and foldable and made to fold flat when not in use. The Canterbury Cap is the medieval Biretta, descended from the ancient Pileus headcovering.
In the Catholic Church, where the cap originated, its use is identical to the use of the modern Biretta, into which the cap have evolved into throughout the centuries on the continent.
The clergy are entitled to wear the cap in Anglican churches, where it is worn for processions and when seated to listen to Scripture or to give a homily, but not when at the Holy Table. It forms part of the canonical outdoor clerical dress, along with cassock, gown, and tippet. The cap is made of black velvet for bishops and doctors, otherwise it’s made of black wool.
A similar cap called the Oxford soft cap is worn today as part of academic dress by some women undergraduates at the University of Oxford instead of the Mortarboard. It has a flap at the back which is held up with buttons unlike the Canterbury Cap.
The Tudor Bonnet is also a similar academic cap worn by a person who holds a doctorate.
The Canterbury Cap has four ridges whereas today’s biretta has three.
Other names for a Canterbury Cap