Best Answer: A PhD is a research based degree. Physicians are MDs, Medical Doctors or DOs, Osteopathic Doctors. So to become a physician, you do not need a PhD. Generally, PhDs are awarded in fields outside of medicine. Also, while NPs and Physician Assistants can prescribe medication, they only practice under the supervision of an MD or DO. That is, there are only two types of doctor.
Princeton's WordNet(4.75 / 4 votes)Rate this definition: 1  light, illumination(noun) a condition of spiritual awareness; divine illumination. 2  illumination(noun) the degree of visibility of your environment. 3  clarification, elucidation, illumination(noun) an interpretation that removes obstacles to understanding.
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target.