A defensive covering for the head. See Casque, Headpiece, Morion, Sallet, and Illust. of Beaver.
- A head covering of hard material, such as leather, metal, or plastic, worn by football players, firefighters, construction workers, motorcyclists, and others to protect the head.
- The headgear with a glass mask worn by deep-sea divers.
- A pith helmet; a topi.
- A head covering, such as a balaclava, that is shaped like a helmet.
- A piece of armor, usually made of metal, designed to protect the head.
- Botany The hood-shaped sepal or corolla of some flowers.
- To provide with or put on a helmet.