time dimensions exist, but they are not always refered to as "dimensions"
we experience 1 time dimension normally: an object can move from point a to point b, only if it utilizes a time dimension
but take quantum phsics, which says that until observed, a particle is at all possible locations at once. this particle, at one point in our normal time, will be in points a-1, a-2, a-3, a-4, . . .all the way to a-n, n being the number of places that the particle can be
a particle can also move in the second time dimension without using the first: point a-2 might actually be the same as point b, so if the particle moved from point a-1 to point a-2 (by travelling sideways in time), it would be the same as travelling from point a to b, using our conventional time dimension
but the question of whether to refer to these as dimensions is not decided, although most people do not refer to them as dimensions