Definition - What does Uninstaller mean?
After running an uninstaller, traces of an application still requiring removal may remain, usually in the system registry. These should be removed individually or by using the control panel's add/remove command. In most cases, the uninstall tool is the easiest way to remove an application.
Techopedia explains Uninstaller
Additionally, various uninstallers may be downloaded as separate applications. They work with a wide range of other applications, and some even remove registry entries that cannot be removed by original uninstallers.