Well, there isn't. It's pretty much black and white when it comes to the defintion. I've looked at several articles now just to confirm and they're all saying the same thing.
Prorogation - Suspend
Dissolution - End
Parliament is prorogued at the end of a session, but the same MPs will meet up again after taking a break. (suspending)
When Parliament is dissolved, it is the end of that Parliament, and a new general election must be held before the next one. (ending)
They're actually very different.