This is a good question and one many people don’t understand. Go read your insurance policy and then, when you think you have the answer, come back and read this. I have put it in plain English first. Here it is in English:
We will pay for accidental loss to your car, minus any deductible. Only the highest deductible applies. We will pay for damage caused, other than collision. If there is a loss to a car you do not own that is covered, we will provide the broadest coverage that you have.
Collision means the upset of your car or its impact with another vehicle. A loss is not by collision if it is damaged because of:
Missiles;
Fire;
Theft;
Explosion;
Wind;
Water;
Vandalism;
Riot;
Contact with an animal; or
Breakage of glass.
Great. Make sense now? Probably not much more sense. (Well, hopefully it does if I am good in translating legalese into English.)
Here is the easiest way to think of this: if you hit something other than an animal, it is a collision. Anything else is comprehensive. So, hit a car and it is a collision. Hit a fence and it is a collision. Hit a deer and it is comprehensive. Car is stolen? Flooded? Comprehensive for both.
I hope this clears up this confusion. I get this question a lot and wanted to give you a common sense, plain English answer.