<p><strong>Verb</strong></p><ul><li>(used with object) to modify equipment (in airplanes, automobiles, a factory, etc.) that is already in service using parts developed or made available after the time of original manufacture.</li><li>to install, fit, or adapt (a device or system) for use with something older: to retrofit solar heating to a poorly insulated house.</li></ul><p><strong>Noun</strong></p><ul><li>something that has been retrofitted.</li><li>an instance of updating, enlarging, etc., with new or modified equipment: A retrofit could save thousands of dollars.</li></ul><p><strong>Adjective</strong></p><ul><li>being or characterized by a retrofit: retrofit units.</li></ul><p><strong>End of Response</strong></p>