I beat joemike to the App Store, but dinner intervened, so he beat me to the post. Free, indeed!
That's not the OED!
This is the OED. There's also an
online version for a very nominal $295/year or $29.95/month.
The OED was released on CD-ROM for Mac and PC (for $800) in 1992, but the 2000 update was for PCs only, and further, since the original version was for OS 9, it ran in OS X in Classic Environment only, and only through Tiger. (Running it in Classic was a MAJOR PIA!)
The guy from whom I acquired my 3rd generation copy told me that Oxford had advised him that duplication of their neither up to date nor still distributed software was cool, but I knew people who wanted it, and I didn't care to distribute bootleg $800 software, so I contacted Oxford myself, and they were like "Sure. No problem."
It's too bad I didn't know you back then, because you'd have loved the thing; it was like a gigantic educational toy! You could even go into the prefs and choose different colors for different aspects of the text.
I'm sorry to say that being an inveterate cleaner-upper I destroyed my copy after a few OS X versions of its obsolescence, because I never expected to find anyone who was that far behind the times.
Damn! I really should have saved it, if only as a cherished relic.