Dimension
Definition one/Spatial
When referring to Spatial Dimensions, this means what dimensions a place has, like 3D, 2D, etc. From research, higher forms of dimensions can go to lower spatial dimensions, for example, Mario(3D Being) becoming Paper Mario(2D being). However, we haven't seen a 4D Mario, as he cannot comprehend that spatial dimension, just try to make something that four dimensional, just try. Higher dimensional characters have been described as either invisible, or just horrific, like causing insanity when seen. Kinda brings Cthulu to mind. Makes sense actually. If Cthulhu was a higher dimensional being, we can explain how people who see him go insane, and where he gets his powers from, also explains where the Moon Lord gets his powers. Being higher dimensional would, by default, make them stronger than lower dimensional. The higher dimensional beings could be human in that dimension, but could be god-like in lower dimensions.
Definition two/Pan
Pan-Dimensional is a portion of Metaphysics, which takes into consideration the world we live in. Pan-Dimensional means something existing between multiple temporal or spacial universe/dimensions and can, in some way, control all of them. However, this is usually complicated both to us (As explaining it is confusing enough) and the being who is pan-dimensional. If a being was separated into eleven universes, and you have to control each an every single one, for every thought, every movement, everything because you are aware of every perspective. It would cause you to have a horrible sense of direction and attention. Try moving in multiple different axis of space time while being aware of every perspective, good luck. This, however, gave me something that I could explain how it works, sort of... I can see what Defure means by saying Munar could exist in every Roleplay and still have an explanation how he can exist everywhere. With Pan-Dimensional, it could give us an explanation to how this is possible, Munar is Pan-Dimensional, able to exist in every universe possible and have control over each and every one of them. And how does he control all of them? I just assume practice with it. But it might be one of those things where you'll never get used to, but... we don't know that.
Definition three/Universal
A plain of existence. What most science fiction is based off of. An alternate bubble of space, of possibilities, of existence. This can be said that it's different worlds. And in fact, there is somewhat proof of what I said. The theory goes with the Big Bang Theory. When it happened, the Universe expanded very fast then apparently stopped. But what if it is still expanding and a part of it got ripped off early on, severing the link between the main chunk of space time, and that other chunk? This could maybe prove that alternate universes, dimensions, and worlds exist out there, isolated by the tear from forming. This is what is called the Eternal Inflation theory(Go ahead and look it up, it exists). That universes are being created right now! Every second you live through, another big bang could happen somewhere out there, creating more and more alternate universes. But, as in real life, we don't have the mathematical equations or actual proof that it has or could happen, so we can't be sure. But it could be said that if it actually exists, they could have different physics due to different ways of growing, so the fundamental constants in our world (Like gravity) could be different in another world (Gravitational potion but worse). It then goes to my theory of Compatibility. You have to become compatible to live in another universe. We adapted to OUR physics in our world, but we haven't adapted to the physics of ANOTHER world. The void could be the way we can become compatible, again this is just a theory. Void is supposed to truly be nothing, so we can kinda assume that void has no physics. Not talking about game voids like Minecraft or Orokin. Just void as is in real life. If they have no physics, then we might be able to achieve a state of malleability, able to adapt to another universe. But, there comes to this, a rule we bend a lot in this place, you know how you write with a pencil on piece of paper, then erase it, you kinda still can see the mark. Soon, if the process is repeated enough times, it will go to the point until it can't be erased anymore. This is what would kinda happen if you gone to multiple universes. But instead of a pencil, it's physics, and instead of a piece of paper, it's your molecules. Soon, after constant physic changes, you're molecules will break apart from the stress of constantly changing physics. That's my theory on limits of universal travel for a person though. But please note that I'm talking about physics, not spatial dimensions. You still cannot comprehend a 4D being if you are 3D. It's basically the breaking point. The physics of dimensions you can exist in can change, but not the spatial dimensions themselves.