A hood is a type of headgear or headwear that covers most of the head and neck, and sometimes the face. Hoods that cover mainly the sides and top of the head, and leave the face mostly or partly open may be worn for protection from the environment, for fashion, as a form of traditional dress or uniform, or in the case of knights, an armoured hood is used for protection against bladed weapons. In some cases, hoods are used to prevent the wearer from seeing where they are going. Hoods with eye holes may be used for religious purposes to prevent the wearer from being seen. In the case of Ku Klux Klan members, terrorists, or criminals such as robbers, a hood with eye holes helps prevent identification.

Headgear, headwear, or headdress is any element of clothing which is worn on one's head, including hats, helmets, turbans and many other types. Headgear is worn for many purposes, including protection against the elements, decoration, or for religious or cultural reasons, including social conventions.