Any one of the three physical or spatial properties of length, area, and volume. In geometry, a point is said to have zero dimension; a figure having only length, such as a line, has one dimension; a plane or surface, two dimensions; and a figure having volume, three dimensions. The fourth dimension is often said to be time, as in the theory of General Relativity. Higher dimensions can be dealt with mathematically but cannot be represented visually.
The measurement of a length, width, or thickness.
A unit, such as mass, time, or charge, associated with a physical quantity and used as the basis for other measurements, such as acceleration.