<p><strong>Noun</strong></p><ul><li>Electricity: a lining for a hole, intended to insulate and protect from abrasion one or more conductors that pass through it.</li><li>Machinery: a replaceable thin tube or sleeve, usually of bronze, mounted in a case or housing as a bearing.</li><li>A replaceable hardened steel tube used as a guide for various tools or parts, as a drill or valve rod.</li></ul><p><strong>End of Response</strong></p>