[sourcery]

Until now, "universe" has been completely synonymous with "all that exists." The same used to be true of the term "world" (and it still is, in some usages of the term "world.") The new meaning no longer encompasses "everything that exists," and so leaves us with no single word with that meaning.

[gondramB]

>>Until now, "universe" has been completely synonymous with "all that exists." The same used to be true of the term "world" (and it still is, in some usages of the term "world.") The new meaning no longer encompasses "everything that exists," and so leaves us with no single word with that meaning.<<

Yes, the new definition of a universe is everything that an observer could ever detect.

This "creating a universe idea" is a less important spinoff of what appears to be a new truth:

That rather than expanding more slowly but forever or slowing down enough that gravity eventually would pull it back together - that instead the expansion of the universe appears to be accelerating.

[RightWhale]

We might, following Einstein, say a universe is an inertial space where the laws of physics are uniform in all directions. If there is another inertial space with different laws of physics, it would be a different universe. That is, defining universe as 'all there is' would do away with regimes of physical laws and destroy some possible utility of the word. The term 'world' could remain as 'all there is,' or we might use the neologism 'multiverse,' which ought to be reserved for further possibilities IMHO.