Apple may have accidentally revealed a new naming scheme for OS X.
Among Apple's OS products, OS X is something of the odd one out. With iOS, WatchOS, and tvOS, the home of the operating system immediately precedes the 'OS' designation in the name.
Many have pointed out that MacOS would make more sense for Apple's desktop operating system in the past, and there has been speculation that a change might be on the cards.
Apple seems to have confirmed that change with a bit of a slip. In the FAQ section of Apple's recently updated Environment webpage, the company refers to MacOS alongside its other platforms. There's no mention of OS X.
This since appears to have been changed back to OS X, but 9to5Mac captured the proof with a screenshot.
Related: OS X El Capitan review
Funnily enough, this isn't the first time that MacOS has turned up in official Apple documentation. Last month, an OS X 10.11.4 framework was found using the macOS name, prompting speculation that the next version of OS X would actually be the first version of MacOS.
Of course, the use of macOS in filenames and code isn't unheard of. Apple using the term in public-facing materials is.
Next, take a look at our tablets vs laptops video:
If we were betting types, we might place a spot of money on a MacOS rebrand being announced at WWDC in mid-June.