What is a "porkpie hat"?

A porkpie hat is a type of hat characterized by its flat top and circular crown that resembles a pork pie. It usually has a small brim and is made from a variety of materials such as straw, wool, and felt. The porkpie hat is popular in both men's and women's fashion and has been worn by notable figures such as jazz musicians and actors. It can be dressed up or down, making it a versatile accessory for any occasion.