Okay kiddo, imagine you have a box of toys. You know how many toys are in the box, right? That's one way you can measure it. Another way you can measure it is by looking at how much space it takes up - like if it's a big box or a small box.
In math, we have something called a vector space. Think of it like your box of toys, but instead of toys, we have things called "vectors." And instead of measuring it by how many toys are in it or how much space it takes up, we measure it by something called "dimension."
Basically, dimension is like counting how many different ways you can move in that space. Let's say you have a flat surface like a piece of paper. You can move left and right, and you can move up and down. So that means the dimension of that space is 2 - because there are 2 different ways you can move.
But let's say you have a box that you can move around in. Now you can move left and right, up and down, *and* forwards and backwards. That means the dimension of that space is 3 - because there are 3 different ways you can move.
So when we talk about dimension in math, we're really just talking about how many different ways we can move in a space. It's like counting how many directions you can go in - just like how you count how many toys are in your box of toys!