A Doctor

1. A physician; a member of the medical profession; one who is trained and licensed to heal the sick or injured. The final examination and qualification may award a doctor degree in which case the post-nominal letters are D.O., DPM, M.D., DMD, DDS, in the US or MBBS in the UK.
2. A person who has attained a doctorate, such as a Ph.D. or Th.D. or one of many other terminal degrees conferred by a college or university.
3. A veterinarian; a medical practitioner who treats non-human animals.
4. A nickname for a person who has special knowledge or talents to manipulate or arrange transactions.
5. (obsolete) A teacher; one skilled in a profession or a branch of knowledge; a learned man.
6. (dated) Any mechanical contrivance intended to remedy a difficulty or serve some purpose in an exigency.
7. A fish, the friar skate.

Usage notes

• Doctor is capitalized when used as a title:Doctor Smith
• In the UK and Commonwealth a surgeon (including a dental or veterinary surgeon) is commonly addressed as Mr./Ms./Mrs. rather than Doctor, even if holding a doctor's degree.

Synonyms

• (physician): general practitioner, GP (UK), medic, physician, sawbones (slang), surgeon (who undertakes surgery)
• (veterinarian): vet, veterinarian, veterinary, veterinary surgeon