Let me introduce a word you may know in a way you might not: Orthogonal.

In school, you might learn "orthogonal means perpendicular," which is true in a sense but it gives you a bad idea of what it means, because it implies that something is perpendicular in physical, 3D space. Orthogonal actually means "this is a new, independent thing that doesn't depend on or influence any other thing in this system." Many non-physical things are orthogonal: my choice of hat to wear is orthogonal

When we talk about colors, we can say that RGB "space" is 3-dimensional because it is created from three orthogonal pieces of information, namely the red "axis," the green "axis" and the blue "axis." Likewise, RGBA "space" is 4-dimensional: it has an additional alpha "axis."

I can talk about this in many different contexts: let's say I wanted to decide what videogame I wanted to play, so I picked the following 5 things: I wanted it to be multiplayer, I wanted it to be medieval themed, I wanted it to be a role-playing game, I wanted it to have a survival mode and I wanted it to have a fishing minigame. For all of the videogames I can buy, I can formulate some way of assigning a 5-dimensional coordinate to each of them, for example Elden Ring could be {20, 100, 100, 0, 0} - quick note, the exact numbers don't actually matter for this example. What I now did was construct a 5-dimensional videogame space in which I can assign any given videogame a point.

Does this make sense? I don't know if I'm making sense or rambling, lol - basically, dimensionality doesn't necessarily mean physical special (or even time) dimensions. We are perfectly capable of understanding much higher dimensional spaces when they have to do with other things like videogames, or buying a house, or watching a movie. We just seem to have trouble picturing geometric shapes and things in higher dimensions than 3, but that is just one specific application of a very general notion in math.

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You said elsewhere in the post that you haven't taken any linear algebra classes - if I can proselytize for a moment, I would highly suggest you try it if you have the ability! It's an extremely beautiful field of math, and it will completely change the way you see many things. It's the "father" field to many important concepts in things like computer science, and thus is very relevant to many things we rely on these days. I think you'd enjoy it, given what you seem to be interested in learning about by asking this question!