Consider a co-ordinate.
For example, (4,3).
It is a point.
It has a position, but no height or width or length.
It is zero-dimensional.
Now imagine stretching that point into a line.
It has become one-dimensional.
It has a length. (Measured in cm, for example.)
Imagine stretching the line out into a square.
It is now two-dimensional. (2D)
It has an area. (Measured, for example, in cm2.)
Stretching this square out results in a cube.
This is a 3D shape. (Three-dimensional.)
It has a volume, which could be measured in cm3.
Notice how the power after the unit shows us how many dimensions are involved.
- cm = cm1 (one-dimensional)
- cm2 (two-dimensional)
- cm3 (three-dimensional)
We could go further, but we’ll leave it there for now.