Hello,
In my country, we learn 3D spaces in the final year of high school
The four dimension space is mostly use by physicists, I guess it is in relativity
As for mathematics, there is an infinity of dimensions. For example, matrices illustrate this, since their dimension can be any nonnegative integer n.
There are a lot of applications (in analysis, algebra or calculus...) where you use

. An element of it is in the form
)
where n is arbitrary.
And there are quite a lot of applications, but we don't quite use it for graphic representations.
Example :
The distance from a point
)
to another point
)
in

is defined as being :
^{\frac 1n}=\left(\sum_{i=1}^n |x_i-y_i|^n\right)^{\frac 1n})
(you can check that this works for p=2 and gives the formula you know).