<p><strong>Verb</strong></p><ul><li>(used with object) to exchange, barter, or trade, as one thing for another.</li><li>to substitute (one thing) for another (sometimes followed by in).</li><li>to replace (one thing) with another (sometimes followed by out).</li></ul><p><strong>Noun</strong></p><ul><li>an exchange.</li></ul>