|This article is written from the|
|Real World point of view|
A dimension is a particular point in space, used to describe the location of matter.
Dimensions known to Man
- First Dimension: Spatial: Up/Down
- Second Dimension: Spatial: Left/Right
- Third Dimension: Spatial: Forward/Backward
- Fourth Dimension: Time
Identified spatial dimensions
Classical physics has theorized that there are three physical dimensions. These dimensions have been made apparent in the movement of an object from a particular point in space, those being up/down, left/right and forward/backward.
Movement in all other directions can be established by a linear combination of two or more of these dimensions. Thus, an object that has moved diagonally through a space has really moved through a combination of the dimensions left/right and forward/backward. This definition has been summarized through referring to one-dimensional objects as lines, two-dimensional objects as planes and three-dimensional objects as cubes. 
Time has been both suggested and considered to be the "fourth dimension." It is not experienced in the same way that the three spatial dimensions ever have been, in that there is only one dimension of time and, although theries have speculated otherwise, time appears to proceed only in one direction. Its unique nature can be used as one way to measure physical change. 
Theoritical physics has suggested in proposals such as string theory and M-theory that physical space in general has many more than four dimensions, in fact 10 and 11 dimensions, respectively. It has been predicted that these additional dimensions are spacelike, but as humans only perceive three spatial dimesions, no simulations or experiments have resulted in conclusive evidence of any extra dimensions. 
The elusive quality of these other dimensions have resulted in a variety of possible explanations. One was the suggestion that space acts as a coil and curls up the extra dimesions on a subatomic scale. potentially at a quark/string level of scale or below. A less accepted alternative explanation has been the proposal that "dimensions beyond the fourth progressively condense timelines and universes into single spatial points in the above dimension, until the tenth, where a 0-dimensional point equates to all possible timelines in all possible universes."
The Twilight Zone
The Twilight Zone inhabits the fifth dimension according to The Narrator. On appearance, the general population of Earth has never seemed aware of the ability of passage into or even evidence of the existence of dimensions beyond the four known to man. (TZ1: "Where is Everybody?")
This fifth dimension overlaps or connects to the lower dimensions, possibly through wormhole-like anomalies, allowing those that exist in those dimensions to enter it, with often unexpected results, such as time anomalies (e.g., time warps, time loops, alternate timelines, etc.), animation of non-living objects, and encounters with entities and energies thought to exist only in conjecture. (TZ1: "The Last Flight", "Living Doll", "It's a Good Life", "Escape Clause")