Modern Pork Pie hats are defined by their crown which resembles the top a pork pie.
I call this a modern Pie hat since other styles in history have also used this name.
I associate this hat with Gene Hackman in the French Connection.
Modern pork pie hats can be made from felt, straw, tweed, leather or like this one a stiff hessian like material. They always have similar proportions to the one I'm wearing, i.e. a small brim which can be flat or curled and upright crown, with the pork pie top.