The four basic parts of a hat are the crown, brim, sweatband and hatband. The crown is the part of the hat that fits on a person's head. The brim is the stiffer material that is attached to the base of the crown and circles the crown either partially or completely.
The sweatband is the small, cloth band that is inside the hat. It is located at the base of the crown and completely circles the inside of the crown. It is this part that touches the person's head, usually around the forehead, when wearing the hat. The hatband circles the outside of the crown at the juncture of the crown and the brim. The hatband can be made of several different materials, including ribbon, string, leather or velvet. This part of the hat is often decorative but also has the practical function of keeping the hat from losing its shape.
Different kinds of hats may have different sized brims. For instance, a baseball cap has a wide brim, but the brim is only present at the front of the hat. A fedora, a dress hat typically made of felt, has a medium brim that circles the hat. A skull cap, a close-fitting cloth hat, has no brim at all.