The way I like to approach this is as follows: In the subjects of sets, the universe is defined as the set that contains all possible elements (it doesn't contain all possible sets, because then that becomes paradoxical, just the elements). When I apply that definition to cosmology, it is obvious that everything that exists would, by definition, exist within the universe. We can say the universe is that which contains all that exists. This naturally answers the question of what is outside the universe. Nothing is outside of it because if there was something outside of it, then that something would be a thing that exists, which by definition would have to exist in the universe.
The boundaries of the universe are determined by the boundaries of the dimensions. In Cartesian coordinates, the universe goes as far as x, y, and z does and exists at every moment to which a value for time can be ascribed. So if there are limits to the universe, that must be because there are limits to x, y, and z. So there can't be a "beyond the edge of the universe" because that would mean there's more points on, say, the x-axis, which is clearly contrary to the premise of there being an edge.
But let's examine the existence or possibility of existence of an edge. There's this thing called the observable universe. This represents the small corner of the universe centered on us and contains literally everything we can observe (that which contains everything that exists and that we can observe; it's an appropriate name). Because we can't observe anything outside the observable universe, we can't know anything about that stuff (okay, there are some things that used to be in the observable universe that aren't anymore, so we can know, at least, that some stuff exists outside of what we can observe, which is a remarkable amount of knowledge about that stuff, when you think about it). As a result, we rarely discuss anything outside our observable boundaries and you frequently hear cosmologists refer to the observable universe as simply "the universe" (sure, it's a bit self-centered, but technically so is the observable universe, so I feel okay doing it too). With that in mind, we can easily determine the limits of "the universe". There's a few different horizons that you could use to define the relevant limits of the universe, but the most often cited number is that the radius of our universe is on the order of $45$ billion light years, which is about $\frac{1}{\sqrt 2}$ times Avogadro's Number in kilometers. That's slightly farther than Usain Bolt can run in an hour.
There's a number of cosmological theories that have different flavours of multiverses (mmmmmm..... vanilla universes). Some of them have the multiverses co-existing with our own, where there isn't physically a time or spatial separation, but another dimension they define to separate them. That makes things mathematically simple, but conceptually tricky. Some define "regions" like our universe that exist alongside similar regions all within larger regions of "not like our universe". These are also a bit varied in how they define "alongside", but usually it's a definition that ends up hurting your head the first time you read it because (here comes the head hurting part) it allows them to be in physically different times/places but still have the possibility of the dimensions of each universe region extend infinitely. I know, but you said you wanted words and that's the best I can do without lots of math and Richard Feynman. But, as the old woman said to her husband in bed, "Where's your point?". My point is to answer your fairly broad question about multiverses. Some theories don't require a grand container for them all, others will simply apply the term "universe" to regions like that we live in (which I personally see as a misuse of the term, but I'm not the labeling police, so they're probably fine) and then define a container for them all. For the latter cases, you'll find terms from as grandiose as "Cosmic landscape" down to as mundane as "background universe". But this has been a confusing and unhelpful sojourn into the world of multiverse theories. In all cases, you can still choose to define "universe" as that which contains all that exists. And in all cases, it doesn't answer the "What's the limit of the universe?" question, all it does is shift it to "What's the limit of the multiverse?". So, let's move on.
The last thing I want to touch on is what opinions you'll generally find. A large number of cosmologists like to say there is more evidence pointing to the universe being flat, and most of them would also say it is infinite in extent. So that would mean the universe doesn't have limits. It just extends outwards forever. You'll certainly find some that say there is a finite but unmeasurable volume to the universe (I very much doubt you'll find reputable cosmologists who seriously say the volume of the entire universe is measurable), but most would agree that we really can't be perfectly sure about that. Now, having a finite volume does not mean there are edges or boundaries. Think of the game Asteroids; the screen has a finite area, but there isn't any edge or boundary that you can fly your triangle into or go beyond (note that I'm not saying you can keep traveling one direction in the universe and wind up back where you started, I'm just giving an example of a finite region with no boundaries). I'll bet some physicists also claim the universe has boundaries or edges. I've never met one, but I'm willing to bet they exist. Still, the predominant thought is that the universe is infinite in spatial extent, which answers the question of whether or not it has limits. The answer is a resounding "No".
To sum up, the universe isn't thought of, for the most part, as having any limits or edges. You can speak of the observable universe, which has a boundary most often cited as $45$ billion light years away. There is no "outside the universe" to speak of, according to most experts. In the case of multiverses, the theories have different stances; some have background universes to contain them all. The way that's most helpful for me to think about the universe is to define it as "that which contains all things that exist", which naturally answers many of these types of questions.
Hope that helps and doesn't confuse further
