When people hear the word dimension, it's often considered mysterious, such as from blockbuster films. But in reality, the concept is actually quite simple. A dimension is, simply put, an independent direction you can move in.Let's begin with the first dimension. You can imagine this as a line, one that stretches forwards and backwards. You can also add the second dimension which allows movement up and down too.Look on a flat sheet of paper. Add the third dimension, depth, and that's the universe we live in ...