Professor (noun)

1. A teacher of the highest academic rank in a college or university, who typically has the ability to conduct original research and to supervise graduate students.
2. A teacher of a specific subject, typically in a school or college.

Origin:

Late 16th century: from latin professor "teacher, public speaker", from profiteri "claim publicly", from pro- "forth" + fateri "acknowledge". the term originally denoted a public teacher of rhetoric or philosophy, later one in a university, and now one in any institution of higher education.

Examples:

1. The professor was respected by all of his students.
2. He was appointed as a professor of mathematics.
3. The professor gave a lecture on the topic.
4. The professor's research was published in a prestigious journal.
5. He learned a lot from the professor, who was an expert in his field.