What is spatial dimension?

Answer 1

Spatial (infrequently spelled spacial) dimensions are those which we normally associate with the characteristics of height, length, width. It would be correct to say that a cube has three equal spatial dimensions. The term dimension is used to refer to the size of something, so spatial dimension is the aspect of the physical extent, or spatial extend, of an object. One may also speak of other measurements of size, the one frequently juxtaposed with spatial is the temporal extent of something. A person's age is a size in the time dimension. The universe is known to have three spatial dimensions and one time dimension. (Theoretical physics has produced conjectures that there are actually more than these four, string theory being one area of current research which asserts the possibility that there are actually 10 or 11 or more dimensions in the universe.)

The concept of dimensions is not limited to space and time. In mathematics, the size of an array of N rows and M columns is said to two-dimensional and N is the column dimension and M is the row dimension. This idea generalizes to more than just two and can even be extended to include the concept of infinite dimensional objects. The concept of size or extent, hence the concept of dimension, goes beyond physics and mathematics and one can, for example, speak of the color dimensions something may have.

In short, a spatial dimension refers to physical size in one direction in space and there are three spatial dimensions and one temporal dimension that are intrinsic to the universe in which we live.