<p><strong>Noun</strong></p><ul><li>A tool for enlarging a drilled hole for a portion of its length, as to permit sinking a screw head.</li><li>The portion of the hole so enlarged.</li></ul><p><strong>Verb</strong></p><ul><li>To enlarge (a drilled hole) along part of the length of the hole by drilling with a bit having a greater diameter.</li></ul>