system
Given the following post, respond as if you're commenting on Reddit:
human
[generic or classical sci-fi] How to describe dimensionality in other terms?

A popular way to reference other universes in less technical terms is to call them other dimensions, but this term has its own peculiarities that logicians love to make hay about.

"A dimension is just length, width, depth, or time," they may say. "How can you visit a whole other dimension like it was a separate universe?"

But if we start redefining things, the apparent contradictions will go away.

So what if a different term was used for the different axes of three-space?

A point in space simply exists, a singularity. A ray can emanate from it, but can only describe direction or length. Add a turn, and you define a flat two-space, length multiplied by width. Add a second turn, and you have a volume or three-space, length multiplied by width multiplied by depth. This plus time makes a spacetime, or a complete dimension. So how many turns? Technically three: length is the zeroth turn. A dimension has three turns emanating from a singularity. With a time arrow that three-space is allowed to have a past and a future, not simply a singularity of an eternal present. It is allowed to change and to experience entropy.

Most dimensions seem to share the same time arrow. You start in one diemsnion, travel to another and spend one hour there, then come back--one hour has also passed in the first. There are dimensions where time goes faster or slower, but these are rare.

Finally, some dimensions have a "3rd turn": hyperspace or subspace, an ethereal or shadow realm that corresponds to multiple frequencies or vibrations or energy levels of existence. Objects and creatures existing at different frequencies may slide through each other or be invisible to each other, but they are still existing in the same dimension of spacetime. And perhaps there are even more turns than these than we can dream of in this philosophy.

Thus: whenever a character or a narrator talks about dimensions as universes, they are talking about universes made of three (or more) turns plus a time arrow, might they not?
gpt
Take a potato and slice it thinly.  Each thin slice would have a slightly different shape, different feel.  You could take a thin slice and cut a hole in it, and the slices next to it would be unaffected.  Now take all the slices and stack them back up so they're in the shape of the original potato.  You can travel between the slices just by moving down the potato.

All you're doing is stepping between slices of the potato.