A bonnet is any of several kinds of head covering, especially a woman's or girl's hat, that tie under the chin and have a brim which frames the face. The name has been applied also to various other kinds of head covering. In Scotland, for example, a soft woolen cap worn by men is called a bonnet. Men in 12th century Byzantium wore bonnets that tied under the chin but were brimless like helmets.
Bonnets for women reached their greatest popularity in the late 18th century and early 19th century. They appeared in many styles: some were soft caps with brims consisting only of narrow ruffles; others were nearly all brim, very stiff and standing far out in front of the face. Among the classic styles that evolved during this period are the "Quaker" bonnet, with a plain wide brim and a slightly gathered crown; the poke bonnet, with a flared brim sometimes trimmed on the underside; and the sunbonnet, with a deep ruffle to protect the shoulders.