What Does One Mean by “the Universe”?

I have a question about contemporary cosmology and how the word "universe" is often used. As you know when a proponent of the Kalam argument uses the word universe" they mean "the entire space time manifold." However a while ago on the forums and on the link at the very bottom somebody pointed out that when physicists like Vilenkin use the word "universe," they are using it differently than proponents of Kalam are. He then gives a quote (via email correspondence apparently) from Vilenkin saying
It is certainly more than what we can have access to. Regions beyond our cosmic horizon are included. But if there are other universes whose space and time are completely disconnected from ours, those are not included. So, by “universe” I mean the entire connected spacetime region.--Alex V.
If this is true then what does this do for the scientific evidence that you and Craig use to defend premise (2) of Kalam? Thanks for your time.
Source of the quote comes from here: http://debunkingwlc.wordpress.com/2012/03/03/universe-kalam-and-equivocation/
Truthseeker
Click HERE to read Dr. Craig's response