<p><strong>Noun</strong></p><ul><li>A back in football who usually lines up immediately behind the center and directs the offense of the team.</li><li>The position played by this back.</li><li>A person who leads or directs a group or activity.</li></ul><p><strong>Verb</strong></p><ul><li>To direct the offense of (a team).</li><li>To lead or direct: to quarterback a public-relations campaign.</li><li>To play the position of quarterback.</li></ul>