Headgear
Headgear, headwear or headdress is the name given to any element of clothing which is worn on one's head.
Headgears serve a variety of purposes:
protection (against impact, cold, heat, rain and other precipitation, glare, sunburn, sunstroke, dust, contaminants, etc.)
to keep hair contained or tidy
decoration or fashion
religious purposes
medical purposes
modesty; social convention
distinction; a badge of office
Overview of headgear types
Bonnets
Bonnets, as worn by women and girls, were hats worn outdoors which were secured by tying under the chin, and often which had some kind of peak or visor. Some styles of bonnets had peaks so large that they effectively prevented women from looking right or left without turning their heads. Bonnets worn by men and boys are generally distinguished from hats by being soft and having no brim—this usage is now rare (they would normally be called caps today, except in Scotland where the "bunnet" is common in both civilian life and in the Royal Regiment of Scotland).