Or does it even matter?

As I mentioned yesterday, I'm editing a ton of question titles. I tend to change OSX to OS X just out of personal preference, but I wonder if that will annoy anyone?

  • 7
    Oh it matters ;-) this crowd is picky, detail-oriented, and very vocal
    – bmike Mod
    Commented Jul 29, 2011 at 18:31
  • @bmike thus the barrage of teeny jargon-related questions! CHAOS has a strict no-toe-stomping policy.
    – hairboat
    Commented Jul 29, 2011 at 18:32
  • You are off to a great start - getting consensus, asking - but taking action nonetheless :-) This joint is starting to look "real classy".
    – bmike Mod
    Commented Jul 29, 2011 at 18:38
  • Detail-oriented? Moi? Probably avidly so, and it's the attention to detail (amongst other things) that makes this joint all the classier :-) Commented Aug 1, 2011 at 14:46
  • Wait, why is this on the meta? Shouldn't this be on the main site?
    – 10 Replies
    Commented Dec 5, 2016 at 21:31

4 Answers 4


This is now a historical curiosity since macOS replaces OS X. And we have a new data point with the iPhone X in writing being verbalized as iPhone 10 when spoken.

Apple's Mac OS X Lion website, documentation, and marketing material all have spaces between OS and X. I'd assume OS X is the correct way to spell OS X. Sidebar, Mac OS X is pronounced Mac Oh Ess Ten, not Oh Ess Ex. This can be confirmed by using the say command in the terminal:

$ say OS X             # Returns Oh Ess Ten
$ say OSX              # Returns Oh Ess Ex
$ say X                # Returns Ex
$ say Roman numeral X  # Returns Ex

Also, as noted by michaelmichael the proper spelling would be Mac OS X.

  • 3
    That's what I thought. We just like to be careful - sometimes people get snippy when we bust in and rearrange all the furniture! (To wit: meta.english.stackexchange.com/questions/1666/…)
    – hairboat
    Commented Jul 28, 2011 at 15:25
  • Is there any footage of Jobs saying "Oh Ess Ten"?
    – John
    Commented Jul 29, 2011 at 10:36
  • 1
    Almost certainly. If not steve-jobs, I have certainly heard other Apple people speak the word "ten" (never heard Apple say "X"). Commented Aug 2, 2011 at 16:02
  • 1
    apple.com/quicktime/qtv/earningsq311 at 13:33 on the timeline, "First: when we deliver Mac OS X Lion …" (pronounced ten). Commented Aug 2, 2011 at 16:08
  • As well as the website, I like to refer to the various versions of the Apple Style Guide, e.g. help.apple.com/asg/mac/2013/ASG_2013.pdf. (They revise it every few years, and I haven't checked recently.) Commented Aug 4, 2016 at 4:33
  • Great answer, but at some point since Lion, Apple adopted the terminology OS X. And now (2016) we have macOS Sierra. In writing specifically about Lion (for exampe) I still like to include the version number and write "OS X 10.7 Lion", at least at the first appearance in the piece. Commented Aug 4, 2016 at 4:36

Now it is neither! As of June 13, 2016, the name has been changed to macOS https://www.apple.com/macos/sierra/

enter image description here

During the keynote at WWDC on June 13, 2016, Apple announced that OS X would be renamed macOS to stylistically match Apple's other operating systems, such as iOS, watchOS, and tvOS.

  • @JeremyDouglass uh... definitely didn't just edit and change that just now because I didn't notice lol.
    – 10 Replies
    Commented Dec 22, 2016 at 1:15
  • 1
    Upvote for the real-time error correction feature on this answer. Which may be needed if Apple keeps changing the <strike>Mac OS X</strike> <strike>OS X</strike> macOS branding.... Commented Dec 22, 2016 at 1:19

To be really nitpicky, it's Mac OS X. They're fanatical about this in Apple Store retail training.

  • Is that something I should be striving for when I'm editing? Or is it "colloquially" ok to just leave it at OS X?
    – hairboat
    Commented Jul 29, 2011 at 15:09
  • 3
    You know what? I stand corrected. Even though apple.com/osx 404s, all the branding on apple.com/macosx talks about OS X Lion - no "Mac". Perhaps they've changed their stance since I heard the above anecdote. I'm sure it won't matter much unless Mac OS is still in version 10 by the time iOS reaches its 10th version. Commented Jul 29, 2011 at 15:19
  • 2
    Yeah, they changed their stance with Lion for some reason and are using "OS X" on the website and marketing material. Though for some reason they still use "Mac OS X" in the actual software. Bizzare... Commented Jul 29, 2011 at 18:26
  • 2
    It's always been Mac OS X for a long time, but the people that "read the tea leaves" and watch each slide of every keynote that apple publishes have noticed Apple to start to write OS X when it used to always have Mac before the OS. Long time observers feel some references to OS X may stand alone when referring to commonality between iOS and Mac OS X. Best to use Mac until the stand alone usage gains traction or it's clearly meant to be inclusive of iOS and Mac OS X.
    – bmike Mod
    Commented Jul 29, 2011 at 18:39
  • Thanks michaelmichael, I updated my post.
    – Aaron Lake
    Commented Aug 4, 2011 at 14:17


I should:

  1. always discourage OSX (with or without a Mac prefix)
  2. encourage Mac OS X whilst Apple support and licensing for OS X is limited to Mac hardware — currently in Apple — Legal there is no OS X without Mac; System Information in the first release of Lion describes Mac OS X …; and so on
  3. without wishing to speculate, consider the possibility that Apple may one day license OS X for use on hardware that is not Mac — not to be confused with past and present OSx86 (Hackintosh) approaches.

Related (but not listed as such in the sidebar)

What is the difference between [mac] and [apple]? (2010-08-17) — AFAICT focused on tagging

On the right name of Apple products and softwares (2010-08-18)

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