The fifth dimension is a variation in the fourth dimension (usually considered time). When, at the same moment in time, a particle can be in two different places, then it must be described with five dimensions. Wave function may be equivalent to the fifth dimension.

One way of looking at the fifth dimension is with multipathism, which views it as parallel possibilities.

It is possible there are many valid ways to view the fifth dimension, and maybe even many valid fifth dimensions. This view is called dimesplitism.