Question: I've found some references, [when looking for information on WAIK installs of Windows 8](http://www.eightforums.com/installation-setup/6824-professional-core-editions-windows-8-both-rp-setup-iso.html) of a varient called Windows 8 core, that can be installed off the professional edition disk. There's also a mention of it [on Win Super Site that says](http://www.winsupersite.com/article/windows8/windows-8-144015) 

> 
> The cheapest, called MSDN Operating Systems, costs $699 a year ($499
>  renewal), and of course includes Windows 8 (Core), Windows 8 Pro, and
>  Windows 8 Enterprise. You get five licenses each for Windows 8 Core
>  and Pro, and one Multiple Activation Key (MAK) for Windows 8
>  Enterprise.
> 
> 
> 

What is Windows 8 core? Is it the new 'home' edition or something else? What differentiates it from the pro and enterprise editions?

Answer: 
Windows 8 (Core) is simply Windows 8. It's the base (core) product, which Pro and Enterprise built on.

And I say that because I can find no official reference to a *Core product* and it was in parenthesis in your source (compared to the other editions where no parenthesis was used).
It means the "Home" edition for all intents and purposes. Perhaps the best source for this is MSFT's own site (for Windows programmers). Search for "PRODUCT\_CORE" here (which programmers rely on) and look at the "Meaning" column:

<https://msdn.microsoft.com/en-us/library/windows/desktop/ms724358(v=vs.85).aspx>

Note that it currently refers to it as "Windows 10 Home" but all other editions have their own qualifiers (e.g., search for "PRODUCT\_PROFESSIONAL", "PRODUCT\_ENTERPRISE", etc.) In fact, prior to the release of Windows 10, the "Meaning" column for "PRODUCT\_CORE" (at the same link) referred to it as simply "Windows 8", which normally means the home edition by default (in the absence of the terms "Pro", "Professional" or "Enterprise").