We know what it means when we say that our universe is three-dimensional: it means that we can move in three orthogonal directions: left-right; up-down; forwards-backwards.
But what would it mean to say that a universe is 2½-dimensional?
Or 3.37-dimensional?
Or 9-dimensional?
When I measured the dimensionality one of Wolfram’s graphs, I found it to be at least 3.37-dimensional.
If Stephen Wolfram is right, then our universe might not be uniformly three-dimensional.
So maybe dimensionality isn’t quite what we think it is.