A hat is an item of clothing which is worn on the head ? a kind of headgear. Hats often have a brim, and may be either placed on the head, or in the case of some women's hats, secured with hat-pins (which are pushed through the hat and the hair). Depending on the type of hat, they are typically worn exclusively by men, women or by either sex.
Parts of a hat can include the following:
Crown - the portion of a hat covering the top of the head
Bill - a projection of stiff material from the bottom of the hat's crown, typically forward, and usually for shading the eyes (also "peak")
Brim - a projection of stiff material from the bottom of the hat's crown horizontally all around the circumference of the hat