A person who is qualified to treat people who are ill.

A person who is highly skilled in a specific profession or field.

किसी विशेष पेशे या क्षेत्र में कुशल व्यक्ति।

English Usage: She is a doctor of philosophy, specializing in ancient history.

Hindi Usage: वह दर्शनशास्त्र की डॉक्टर है, जो प्राचीन इतिहास में विशेषज्ञता रखती है।