Indeed, you can see between 2011 and 2012 (for example) that Apple's PR site changed from calling it "Mac OS X" to simply calling it "OS X". 2011: https://web

Indeed, you can see between 2011 and 2012 (for example) that Apple's PR site changed from calling it "Mac OS X" to simply calling it "OS X". 2011: https://web.archive.org/web/20111130104524/http://www.apple.com/pr/products/ https://web.archive.org/web/20111130104524/http://www.apple.... 2012: https://web.archive.org/web/20120222083925/http://www.apple.com/pr/products/ https://web.archive.org/web/20120222083925/http://www.apple.... Interestingly Lion was called "Mac OS X Lion" upon release[0], but then their website[1] called it "OS X Lion" predominantly. [0] https://www.apple.com/newsroom/2011/07/20Mac-OS-X-Lion-Available-Today-From-the-Mac-App-Store/ https://www.apple.com/newsroom/2011/07/20Mac-OS-X-Lion-Avail... [1] https://web.archive.org/web/20110705041542/http://www.apple.com/macosx/ https://web.archive.org/web/20110705041542/http://www.apple....