<p><strong>noun</strong></p><ul><li>a short coat, in any of various forms, usually opening down the front.</li><li>something designed to be placed around the upper part of the body for a specific purpose other than use as clothing: a life jacket.</li><li>a protective outer covering.</li><li>the skin of a potato, especially when it has been cooked.</li><li>book jacket.</li><li>the cover of a paperbound book, usually bearing an illustration.</li><li>a paper or cardboard envelope for protecting a phonograph record.</li><li>a metal casing, as the steel covering of a cannon, the steel cover around the core of a bullet, or the water jacket on certain types of machine guns.</li><li>a folded paper or open envelope containing an official document.</li></ul><p><strong>verb</strong></p><ul><li>to put a jacket on (someone or something).</li></ul>