If you think about it, OS X isn't really a great name for Apple's Mac operating system. It was just meant to be the next OS after Mac OS 9, but because it has a nice round (roman) number and used all-new UNIX-based tech, Apple has stuck with the name for nigh on 17 years. According to the rumor mill and apparent slip-up on the App Store, that's about to change, however. It now seems likely that Apple will change OS X to macOS, essentially reverting to its pre-1999 naming scheme.