In science we attempt to classify everything. And everything seems to be a subset of something else. Planet is a part of a solar system, solar system is a part of a galaxy, galaxy is part of the universe, universe is a part of our dimension, etc.

Obviously there are exceptions to this, rogue planets, but we still consider them contained.

I understand the idea of multidimensions is theoretical, but if they exist, do we have a name or even a theory what might contain them?

      • It sounds like you got it basically right, but now think about the sentence “the universe is a part of our dimension” which would mean “the universe is a part of our universe”.

        The scifi “dimension” is as meaningless as “plane of existence”; it just sounds nice when you want to explain things away in scifi. I mean, it seems to be easier in scifi to travel between those “dimensions” than between the Milky Way and any other galaxy in the visible universe.

        • The scifi “dimension” is as meaningless as “plane of existence”

          Does not sound too meaningless to me, but I’m used to calling that a universe 😁

          think about the sentence “the universe is a part of our dimension”

          I’m trying ahah. But if you call the universe a dimension, which subpart of it do you call a universe? The observable universe maybe? I mean it makes sense to say that the observable universe is part of our universe. Still sounds strange the way it is presented by OP.