Off the top of your head

A. What would you say is the difference between a realm, a dimension, a void, and a default? What do they each consist of?

B. Can they be in each other and be so, with or without, effecting each other? Can they each stand alone?

C. What is considered in classified proof/knowledge either of them?
Express examples of them each if you can.

I figure the paranormal fans and/or space exploration fans may have the scoop.