What is the difference between dr and DR. and DR?

Answer 1

There is no difference between Dr and DR and DR. when used to show that a person has a doctorate in medicine or botany or other subject.

However, Dr. is the preferred abbreviation, as in Dr. Smith. This follows the pattern of Mr. and Mrs. in using a capital followed by small letters and a period to show that it is an abbreviation.

Only the letters that come after the person's name can tell you if the person has an M.D. (Medical Doctor) or a Ph.D. (Doctor of Philosophy) or other advanced degree.

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Some people believe that Dr. is dedicated to a medical practitioner. So, DR. should be used for Ph. D holders in other subjects.