The term 'Flat Topper' refers to two different types of headwear: a BERET and a TAM. A BERET is a soft, round, flat-crowned hat that is typically made of wool felt or cotton and is often associated with the military. A TAM is a type of hat that is similar to a BERET but has a slightly taller crown and is usually made of knitted fabric. Both the BERET and the TAM are popular choices for those looking for a stylish way to top off their look.