What does PhD stand for? It stands for Doctor of Philosophy, and the letters follow the Latin order, philosophiae doctor. Despite the name, the degree covers far more than philosophy. It is the highest research degree in most academic fields, from chemistry and history to economics and nursing.
The word philosophy here keeps its older, broad sense of "love of wisdom," meaning serious study of any subject. Someone who earns the degree has carried out original research and written it up in a long work called a dissertation, which a panel of experts reviews and approves.
Quick facts
PhD full form
Doctor of PhilosophyLatin
Philosophiae doctorType
Abbreviation, said P H DSpellings
PhD or Ph.D.Plural
PhDs or Ph.D.sTitle
Dr., as in Dr. LopezNot to be confused with
MD (medical doctor), JD (law degree)
The letters and the Latin behind them
| Letters | Latin | English |
|---|---|---|
| Ph | Philosophiae | Of philosophy |
| D | Doctor | Teacher, learned person |
The "Ph" is a two-letter piece standing for one word, which is why the h is lowercase. The Latin word doctor originally meant teacher. That is a reminder that a doctorate began as a license to teach at a university, long before "doctor" also came to mean a physician.
What does PhD stand for in education?
In the education system, a PhD sits at the top of the ladder. A typical path in the United States looks like this:
- A bachelor's degree, such as a BA or BS.
- Sometimes a master's degree, such as an MA or MS, though many programs admit students straight from a bachelor's.
- Graduate coursework and exams in the chosen field.
- Original research, guided by a faculty adviser.
- A written dissertation and an oral defense before a committee.
Full time students often take five or more years to finish, and the time varies a lot by field. Many doctoral students also teach or work in labs while they study.
On a university staff page: "Maria Chen, PhD, Associate Professor of Biology." The letters after the name tell readers she holds a doctorate, so students may address her as Dr. Chen.
PhD or Ph.D.? Writing it correctly
- Both spellings are accepted. PhD without periods is now common in academic writing; Ph.D. with periods is the choice of many newspapers and some style guides.
- Capitals: capital P, lowercase h, capital D. Avoid PHD or Phd.
- Article: write "a PhD," since P is said "pee."
- Plural: PhDs (or Ph.D.s).
- After a name: "Jordan Ellis, PhD" or "Dr. Jordan Ellis," but not both at once, since "Dr. Jordan Ellis, PhD" repeats the same title.
In conversation, you will hear "a doctorate" or "a doctoral degree" used for the same thing.
PhD vs MD, EdD and other doctorates
A PhD is a research doctorate. Other doctoral degrees prepare people for professional practice instead.
| Degree | Stands for | Focus |
|---|---|---|
| PhD | Doctor of Philosophy | Original research in an academic field |
| MD | Doctor of Medicine | Practicing medicine as a physician |
| JD | Juris Doctor | Practicing law |
| EdD | Doctor of Education | Leadership and practice in schools |
| PsyD | Doctor of Psychology | Clinical work with patients |
Both a PhD holder and a physician may be called Dr. In a hospital, the title usually signals a medical doctor; on a college campus, it usually signals a PhD.
Terms you will hear around a PhD
- Doctoral candidate: a student who has passed exams and is working on the dissertation.
- ABD: "all but dissertation," someone who finished everything except the final research paper.
- Dissertation: the long written report of original research.
- Defense: the meeting where the candidate presents and answers questions about the work.
- Postdoc: a research job some people take after earning a PhD.
For more letters from campus life, such as GPA and degree names, see the school acronyms guide.
Questions people ask
What does a PhD stand for in plain English?
A PhD stands for Doctor of Philosophy. In plain terms, it means the person has done years of advanced study and original research in a field and has earned the highest academic degree in it.
Is a PhD a doctor?
Yes, a PhD holder has a doctorate and can use the title Dr. They are not medical doctors unless they also hold a medical degree such as an MD.
Why is it called Doctor of Philosophy if it is not about philosophy?
The name comes from an older meaning of philosophy as the love of wisdom or learning in general. Over time the title stayed the same for all research fields.
How long does a PhD take?
In the United States, full time students often need five or more years after a bachelor's degree, and the length varies by field and program.
Is the PhD abbreviation written with periods?
You will see it both ways, PhD and Ph.D., and either is fine. Follow the style guide your school, employer or publication uses.