Doctor/Physician

Noun
Medical professional
Current spelling and usage of doctor dates to the 1380s. Wasn't commonplace until 1500s.
Physician is also from the late 1300s.

List of old spellings and equivalent words:

1. Doctour (Middle English)
2. Physitian (1600s-1700s)
3. Physick (1600s-1700s)
4. Fisicien (Middle English)