<p><strong>Adjective</strong></p><ul><li>Fourfold</li><li>Consisting of four parts: a quadruple alliance.</li><li>Four times as great.</li><li>Music: having four beats to a measure.</li></ul><p><strong>Noun</strong></p><ul><li>A number, amount, etc., four times as great as another.</li><li>Something, as a series of acrobatic somersaults, made up of four clearly defined parts or stages: the first trapeze artist to perform a quadruple successfully.</li></ul><p><strong>Verb</strong> (used with or without object)</p><ul><li>Quadrupled, quadrupling.</li><li>To make or become four times as great: To serve 24 people, quadruple the recipe.</li><li>My savings quadrupled in 20 years.</li></ul>