Quick Reverb Question

I am starting to use reverb more now and have been trying to do a little reading on it. I want someone to confirm some of my understanding and also answer a simple question.

I think that pre delay is the time period before the reverb that is audible to humans starts, before this is some diffuse small reverberations that cannot be heard.

I am assuming this is related to the size of the room and damping etc, the reverb time, is the time the reverb is audible? If so what is the decay? I thought this was the time it took to die away.

Also one final question, on the basic 'cubase reverb b' it has a room size setting and a damping and pre delay and reverb time setting.

I dont understand why the room size setting is there, as I thought this would be perceived as combination of pre delay, damping and reverb time?

Thanks to anyone that can help.

The room size setting changes the feel of the reverb - cavernous or small and tinny.

In reality a cavernous room woudl have a long decay, and a small room would have a short decay but you can tweak the settings to extend the reverb in a small room and have a short but cavernous sounding verb. If you couldn't do that you woud never really be able to go for an epic reverb, as the reverb trail would go on for too long and turn your track into a muddy washy mush.

Damping is the "absorbtion" of high frequencies. Basically like a filter for high frequencies, which don't naturally reverb much.

This is my understanding of reverb - but it couldn't be completely wrong.
Take with a pinch of salt :)