In India a person who has completed the doctoral level academic research requirements is awarded a doctorate degree (most common Ph.D.) by an university recognized by UGC and become entitled by right to be addressed as 'Doctor' and prefix Dr. to his name.
However general practitioners in the field of medicine even though holding a bachelors degree (like MBBS) are called doctors as courtesy to noble profession. Here the word 'doctor' is used as a noun to refer generically to any practitioner of medicine instead of as an adjective to indicate the level of degree obtained by individual practitioner.
Even the practitioners of AYUSH system of medicine (Ayurveda, Yoga, Unani, Siddha, Homeopathy ) are called doctors instead of Vaid, Yogi, Hakim, Siddhar or Homeopath respectively.
MBBS is a professional degree (distinguished from a purely academic degree). A professional degree prepares a student for a particular profession by emphasizing skills and practical analysis over theory and research. Most of the professional degrees are awarded in the field of professions that require licensing or accreditation for practice as a professional in the field e.g. MBBS degree holders require registration with Medical Council of India.
MBBS is a graduate level degree. Postgraduate level education in the stream leads to postgraduate degrees like MD/MS etc.
After post graduate degree in the medical field one can go for doctorate level education in medical field leading to doctorate degree e.g. DM (Doctor of Medicine).
After Ph.D. in academic field one can go for higher doctorate level study leading to higher degrees like D.Sc. (Doctor of Science), D.Litt. (Doctor of Letters), LL.D. (Doctor of Laws) etc.
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