A lot of companies have started calling Comprehensive coverage "Other Than Collision" ( OTC ) - it pays for just about everything BUT a COLLISION or UPSET of the vehicle.
A little clarification is needed by don-sv-az's comment regarding theft of items out of your car. Normally, items in your car are NOT covered, unless they are a permanent attachment such as stereo, speakers and the like. Radar detectors, GPS units (portable), guns, CD CASE with all your CD's (if the unit is stolen out of the dash, they normally pay for one CD - the one that was IN the unit), IPOD, cell phone....items that are LOOSE in your auto are not covered. You might have some coverage on your homeowner's policy for these types of items but normally subject to a higher deductible.
Collision will pay for hitting another car, tree, house, building, etc and for "upset" which could mean collision with the ground - as in "roll over" cases.
Both are normally sold with a deductible. The amounts of deductible vary, and are like a see-saw: the higher the deductible, the lower the premium. The lower the deductible, the higher the premium.
Good luck, drive RESPONSIBLY and I hope this helps!