Well... if you are talking about hosting servers... Dedicated server means the server will only do what you want it to do. You have all of the computers resources at your command. A non-dedicated server is where the resources are shared between multiple users... If you are refering to a game server then dedicated is when your computer just runs the server and non-dedicated is where you are the server AND you play. Hope either of these are what you are looking for.
Phen