Comment Re:multiverse != multiple observable regions in sp (Score 1) 458
There's no standard definition for the term "multiverse", because it's not a term that corresponds to any established physical theory. The theory described in the article has a good claim to the term multiverse, because it's much more than just separate regions.
The region of the universe we're in almost certainly extends beyond the limits that we observe, so there are already "separated observable regions" in the universe we know. The article is talking about a scenario in which multiple Big Bangs occur, so each region is not just separated by distance but also by the nature of the space in that region - how much it has inflated, how fast it is inflating. Each such inflating region is possibly also distinguished by different laws of physics in that region. There would also be non-inflating regions which would have properties different from anything we're familiar with.
Back when other galaxies were first discovered, they were originally referred to as "island universes". This eventually changed to "galaxy" as our understanding of the extent of the universe shifted. If the theory in the article were somehow confirmed (difficult!) then in future, we might indeed refer to that larger space as just "the Universe", and refer to the inflating bubble we're in as something less all-encompassing than "the Universe". For now, though, it would be very confusing if we started referring to speculative constructs way beyond our ability to observe as "the Universe". Multiverse is as good as a term as any.