A beef arm roast—also commonly called an arm pot roast, arm chuck roast, or round bone pot roast—is an economical and deeply flavorful cut of beef sourced from the chuck primal area of the cow's shoulder. It is easily recognized by a prominent circular marrow bone in its center, surrounded by lean muscle tissue. Because it comes from a hard-working muscle group, it contains substantial connective tissue and collagen, meaning it must be cooked low and slow to melt into a tender, fall-apart texture.