In a lot of cases, the fourth dimension is describe as space. But if you were looking into string theory, often times there are description of many spatial dime

In a lot of cases, the fourth dimension is describe as space. But if you were looking into string theory, often times there are description of many spatial dimensions, say 11 spatial dimensions and then a single dimension of time. We could also have multi-dimension time dimensions as well. The idea of parallel universes where at least one decision is made differently from our own could instead be different dimensions of time. Move to the left or right in time and experience different choices as opposed to only going forward as I assume most of us do now. :D