Stew meat and roast is there a dif?

Okay so, I want to attempt to make a pot roast in my crock pot... but as I was searching for recipes, I found recipes for beef stew. Now I would like to try to make that instead. My question is this... If I buy a pot roast or a chuck roast, can I turn that into "stew meat" and if so how... or are they 2 totally different types of beef?