What does Operating System Environments (OSEs) mean on System Center 2012 Licensing?

Question

I was looking into System Center 2010 Licensing Details and came across with this term:

# of Managed Operating System Environments (OSEs) per license

Do they mean regular Operating Systems? or adding "Environments" mean something else (platform, architecture, etc.)?

Thanks

Solution

From the context, we can see that it simply means each unique installation of Windows Server, whether physical or virtual.