Doctor
In a medical context, any medical professional with an MD, a PhD, or any other doctoral degree.
The term doctor is quite nonspecific.
A doctor may, for example, be a physician, psychologist, biomedical scientist, dentist, or veterinarian.
In a nonmedical context, a professor of history might be addressed as doctor, an eminent theologian might be named a doctor of a church, and a person awarded an honorary doctorate by a college or university might also be called a doctor.
The word 'doctor' comes from the Latin 'docere' meaning to teach.
A doctor was a teacher, especially a learned or authoritative one.