The Particle Universe, Part II

What my theory requests is a better definition for what we call a universe. The scientific model of a Universe is: the summation of all particles and energy that exist and the space-time in which all events occur. Based on observations of the portion of the Universe that is observable, physicists attempt to describe the whole of space-time, including all matter and energy and events which occur, as a single system corresponding to a mathematical model. Our universe is also defined as one component part of a larger Multiverse.
My first problem is that the definition is two faced, stating that the universe is everything and corresponds to one mathematical model, and it is also just a single part of a Multiverse (a set of diconnected space-times). Let's examine the grammatical definition of the word universe: derived from Old French univers, from Latin universum, which combines uni- (the combining form of unus, or "one") with versus (perfect passive participle of vertere, or "turn"). The word, therefore, can mean "[everything] rolled into one" or "revolving as one" or "orbiting as one". So, "one-turn", "everything rolled into one", "revolving as one" or "orbiting as one" is the general definition of the word universe. So the "one" is pretty clear, but what is the "turn", "revolving" or the "orbiting?" I have come to two considerations: a universe is 'one space-time' or a universe is 'one physical model.'
Examining 'one space-time' would be that everything that we can observe and test, both at the astronomical level and the sub-atomic level, would answer to one physical model. To make this work we would have to amend the current physical model with a sub-class that deals with the behavior of particles, and perhaps make another sub-class that will deal with Black Holes and Dark Matter. This is o.k. but gets a little messy over time. If we examine 'one physical model' per universe, in a multiverse, there would be a physical model used to describe the particle universe, another physical model to describe our universe (the wave universe), and then another physical model to describe the greater astronomical universe and so on. I feel the many universes in a multiverse theory is much more prepared for the expanding observations we are are making today and will continue to make in the future.