A Doctor of Philosophy (PhD or DPhil) is a type of doctorate degree awarded by universities in many countries. The degree, named after its historic roots as a Doctorate licensed to one allowed to profess a Philosophiae, was formally awarded by European universities since the Medieval era circa 1150-1200. PhDs are awarded for a wide range of programs in the sciences (e.g., biology, physics, mathematics, etc.), engineering, and humanities (e.g., history, English literature, musicology, etc.). The PhD is a terminal degree in many fields. The completion of a PhD is a requirement for employment as a university professor, researcher, or scientist in many fields. A clear distinction is made between an “earned doctorate”, which is awarded for completion of a course of study and thesis or dissertation and an “honorary doctorate”, which is an honorary title granted by a university to a successful or notable person.
The PhD degree varies considerably according to the country, institution, and time period, from entry-level research degrees to higher doctorates. A person who attains a doctorate of philosophy is automatically awarded the academic title of doctor. During the studies that lead to the degree, the student is called doctoral student or PhD student, but also “doctoral candidate” or “PhD candidate” once the student has completed all of the coursework and comprehensive examinations and is working on his or her thesis or dissertation.
A PhD candidate must submit a project, thesis or dissertation often consisting of a body of original academic research, which is in principle worthy of publication in a peer-reviewed journal. In many countries a candidate must defend this work before a panel of expert examiners appointed by the university. Universities award other types of doctorates besides the PhD, such as the Doctor of Musical Arts (DMA), a degree for music performers and the Doctor of Education (Ed.D.), a degree for professional educators.
In India, generally a master’s degree is required to gain admission to a doctoral program. Direct admission to a Ph.D. programme after bachelors is also offered by the IITs, the IIITs, the NITs and the Academy of Scientific and Innovative Research. In some subjects, doing a Masters in Philosophy (M.Phil.) is a prerequisite to starting a Ph.D. For funding/fellowship, it is required to qualify for the National Eligibility Test for Lectureship and Junior Research fellowship (NET for LS and JRF)  conducted by the federal research organisation Council of Scientific and Industrial Research (CSIR) and University Grants Commission (UGC).
In the last few years, there have been many changes in the rules relating to a Ph.D. in India . According to the new rules described by UGC, universities must have to conduct entrance exams in general ability and the selected subject. After clearing these tests, the shortlisted candidates need to appear for an interview by the available supervisor/guide. After successful completion of the course work, the students are required to give presentations of the research proposal (plan of work or synopsis) at the beginning, submit progress reports, give a pre-submission presentation and finally defend the thesis in an open defence viva-voce.