There is no difference between PhD and Dr for professors. The abbreviation “Dr” is used to refer to someone who has earned a doctoral degree, which is the highest level of academic degree. A PhD is a Doctor of Philosophy, which is a research-based degree that typically takes several years to complete.

In some cases, people with other types of doctoral degrees, such as a Doctor of Medicine (MD) or a Doctor of Education (EdD), may also be addressed as “Dr.” However, the title “Dr” is most commonly used for people with PhDs.

So, if you see a professor with the title “Dr,” you can be sure that they have earned a doctoral degree. The abbreviation “PhD” may also be used, but it is not necessary.

Here are some examples of how the title “Dr” might be used in a professional setting:

• “Dr. Smith is the professor of history.”
• “Please make an appointment with Dr. Jones.”
• “Dr. Brown will be giving a lecture on the history of the Civil War.”