WWWebster defines “universe” as follows: Quote: Main Entry: uni·verse Pronunciation: 'yü-n&-"v&rs Function: noun Etymology: Latin universum, from neuter of universus entire, whole, from uni- + versus turned toward, from past participle of vertere to turn -- more at WORTH Date: 1589
1 : the whole body of things and phenomena observed or postulated : COSMOS: as
a : a systematic whole held to arise by and persist through the direct intervention of divine power
b : the world of human experience
c
(1) : the entire celestial cosmos
(2) : MILKY WAY GALAXY
(3) : an aggregate of stars comparable to the Milky Way galaxy
2 : a distinct field or province of thought or reality that forms a closed system or self-inclusive and independent organization
3 : POPULATION 4
4 : a set that contains all elements relevant to a particular discussion or problem
5 : a great number or quantity <a large enough universe of stocks... to choose from -- G. B. Clairmont>
On the CoV, the physical Universe in which we live is always capitalized (a proper nown). We use universii to refer to possible, hypothetical other univerii which are, so far as we know inaccessible to us. Shoulf these hypothesised "other universii" be established to exist, they would immediately become a part of our Uninverse, as the Universe can best be described as the set of all things, real and imaginary which have existence or potential existence. This is not by any means a “stretch.”
You will see that our definition matches the primary definition under 1, 2 and 4 and includes the additional definitions under 1 and subsumes 3 and 5. Is this definition falsifiable. Of course it can be. An example might be, "There is no set of things, real and imaginary which have existence or potential existence which can be defined to be a valid set under set theory." This would suffice to falsify the Universe were it true. The definition is easily demonstrated to be non-axiomatic. From the axioms of union and pairing we are able to prove that the universal membership predicate is infinite and that all other sets are subsets of the universal membership predicate through the axiom of subset (comprehension). The Universe is validated by observation, implied by reason and logic, and other fundamental axioms of reason and logic make no sense if the Universe is falsified. Thus it is probable that the universe as defined does exist and as our definition is an "acceptable and shared" definition, it is useful for communication.