Noun
(Oxford University, otherwise historical) Synonym of Ph.D. (as awarded by Oxford University.)
(Oxford University, otherwise rare) A person who holds a Ph.D. or D.Phil. degree.
(Oxford University slang) Clipping of D.Phil. student.
Source: en.wiktionary.orgThis displaced the existing Doctor of Philosophy degree in some universities; for instance, the D.Phil. (higher doctorate in the faculty of philosophy) at the University of St Andrews was discontinued and replaced with the Ph. Source: Internet
D. (an abbreviation for the Latin Philosophiæ Doctor; or alternatively Doctor philosophiæ, D.Phil., meaning Teacher of Philosophy), or other research doctorate such as the Doctor of Science, or Sc.D. (an abbreviation of the Latin Scientiae Doctor). Source: Internet