If something is inverted, it's upside-down, like an inverted angel food cake that you flipped over so it could cool on the counter after baking. Do a handstand and you have an inverted body, with your head down and your feet up in the air. You know what M.D.

Understanding the Context

means, but what does D.O. mean? What's different and what's alike between these two kinds of health care providers?