A Doctor of Philosophy (PhD, DPhil; Latin: philosophiae doctor or doctor in philosophia) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the degree is most often abbreviated PhD (or, at times, as Ph.D. in North America), pronounced as three separate letters ( PEE-aych-DEE). The University of Oxford uses the alternative abbreviation "DPhil". PhDs are awarded for programs across the whole breadth of academic fields.
https://en.wikipedia.org/wiki/Doctor_of_Philosophy