<p><strong>noun</strong></p><ul><li>any covering for the head, especially a hat, cap, bonnet, etc.</li><li>a protective covering for the head, as a steel helmet or football helmet.</li><li>the parts of a harness about the animal's head.</li><li>a device worn on the head and attached by wires and elastic bands to braces in the mouth, used to create backward tension in the process of repositioning protruding teeth.</li><li>a headframe and its machinery in mining.</li></ul>