<p><strong>Noun</strong></p><ul><li>a portable breathing device for free-swimming divers, consisting of a mouthpiece joined by hoses to one or two tanks of compressed air that are strapped on the back.</li><li>scuba diving</li></ul><p><strong>Verb</strong></p><ul><li>(used without object) scubaed, scubaing.</li><li>scuba-dive</li></ul>