Dimensions: Most will be familiar with the concept of 2-D and 3-D. If something has 2 dimensions: any point on it can be labelled with (x,y) co-ordinates. And anyone who has been to see a 3-D film will know the extra dimension is towards or away.
Although we understand our world looks 3-D, we’re in no way certain. For example some physicist will argue things like electrons and quarks are just points and are therefore 0-Dimensional. However, string-theorists would argue that the world is composed of 1-Dimensional oscillating strings. We believe it is possible that the universe could be a 1-Dimensional line folded in on itself… Or it could be a 4-Dimensional one (theoretical design above)… Or again if you’re a string-theorist: there are 9. Time even has a direction, but then things are getting confusing.
What is a dimension? http://www.youtube.com/watch?v=SJJhHknEDPY&feature=fvwrel
Dimensions aren’t labelled directions: http://www.youtube.com/watch?v=M9sbdrPVfOQ&list=PLED25F943F8D6081C&index=6&feature=plcp