A 0-Dimensional Space is a space in which every position can be described in the point. In other words, there is only one possible position in zero dimensional space, so no information is needed to describe the location.
Strictly, a zero dimensional space will have no time or space so it will be in a fixed and single state, though sometimes spaces with some time dimensions (such as 0+1 dimensional space) are considered to be zero-dimensional.
A verse that is zero dimensional is called a protoverse.