What Label maker can be used on an OS X iMac Lion 10.7.5 ?
You can use a solution from the SmileSoftware called DiscLabel. The application is compatible with OSX 10.6 or later. Use the URL below to access its official website where you can download a trial version of the software.
Installation instructions: https://smilesoftware.com/DiscLabel/download_thanks.html
Additionally, check the database of Mac Informer for alternative software, in case you don't like DiscLabel.