I have a "rock" that was found in Wyoming  in cave where dinosaur bones were discovered  I was told that it most likely is a stone that a dinosaur used for digestive purposes, the man even had a name for that type of stone  Could you help me with a name?  Thank you

The term you want is 'gastrolith'. Only a few dinosaurs had them, and they are generally only associated with smaller plant eating dinosaurs (as with many modern herbivorous birds). They can be told as they are generally found in a mass inside what would have been the dinosaur's chest cavity and they are typcially very smooth (becuase they've been rattling around, possibly with some acid) and tend to be of an unusual geology since they will have been picked up somewhere else by the animal.