医师 (yī shī) is a formal, professional term meaning 'physician' — a licensed medical doctor qualified to diagnose and treat illnesses. The character 医 (yī) means 'medicine' or 'to heal', while 师 (shī) means 'teacher' or 'expert', together conveying the idea of a 'master healer' or 'medical expert'. Unlike the more general term 医生 (yī shēng), which can refer to any medical practitioner including interns or traditional healers in casual speech, 医师 specifically denotes a certified, registered physician who has passed national licensing exams.

This term appears frequently in official documents, hospital signage, medical licenses, and formal introductions. It emphasizes professional qualification and legal authorization to practice Western-style medicine in China and other Mandarin-speaking regions. In everyday conversation, people often use 医生 instead, but 医师 carries greater weight in legal, administrative, and academic contexts — for example, on a clinic’s registration certificate or a doctor’s official title card.