professor

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A college or university teacher who ranks above an associate professor.
2. n. A teacher or instructor.
3. n. One who professes.

Century Dictionary and Cyclopedia

1. n. One who professes; one who openly declares or makes profession of specific belief or views, of adherence to a certain course of action or way of life, or of knowledge or skill in any particular calling.
2. n. One who makes open profession of religious faith and conversion, and attaches himself to some religious denomination. This use, probably originating among the English Puritans, is chiefly confined to English and Scottish nonconformists and their descendants.
3. n. A public teacher in a university, especially one to whom this title has been formally granted. The title, now the highest that a teacher can receive, appears to have originated in the Italian universities. In Oxford and Cambridge, the professors, and the instruction which they convey by lectures, are only auxiliary instead of principal agents, the routine work of instruction being carried on by the tutors connected with the several colleges. In the universities of Scotland and Germany, on the other hand, the professors are at once the governing body and principal functionaries for the purposes of education. In American universities there is generally a professor at the head of each department of instruction, having often other professors and assistant professors under him. The title is often given, also, to teachers of special branches in secondary schools, and locally to principals of common schools (a use derived from the French).
4. n. In a loose use, any one who publicly teaches or exercises an art or occupation for pay, as a dancing-master, phrenologist, balloonist, juggler, acrobat, boxer, etc.
5. n. The name of an artificial fly used in angling.

Wiktionary

1. n. A teacher or faculty member at a college or university.
2. n. A higher ranking for a teacher or faculty member at a college or university. Abbreviated Prof.
3. n. An honorific title for a higher ranking teacher. (Capitalised)
4. n. archaic One who professes.
5. n. US, slang A pianist in a saloon, brothel, etc.
6. n. The puppeteer who performs a Punch and Judy show; a Punchman.

GNU Webster's 1913

1. n. One who professed, or makes open declaration of, his sentiments or opinions; especially, one who makes a public avowal of his belief in the Scriptures and his faith in Christ, and thus unites himself to the visible church.
2. n. One who professed, or publicly teaches, any science or branch of learning; especially, an officer in a university, college, or other seminary, whose business it is to read lectures, or instruct students, in a particular branch of learning; as a professor of theology, of botany, of mathematics, or of political economy.

WordNet 3.0

1. n. someone who is a member of the faculty at a college or university