Longman Dictionary of Contemporary English - professor

~ n especially BrE 1 a teacher of the highest rank in a university department; full professor AmE  (Thank you, Professor Barclay, for your comments. | my science professor | a professor of history) 2 AmE a teacher at a university or college  (Ted's a college professor. | Professor, can I ask you a question?)  (- see also assistant professor, associate professor) 3 a title taken by some people who teach various skills  (Madame Clara, professor of dancing)  ( USAGE NOTE: PROFESSOR BRITISH AND AMERICAN ENGLISH In many countries all university teachers are called professor. In Britain professor is used only for members of the highest rank of university teachers a research professor | Professor Leech is in charge of the department here. Lower ranks in a university are lecturer, senior lecturer, and reader. In the US many more university teachers are called professor, which is used of any full member of the teaching staff of a university or college. There are three specific ranks associate professor, assistant professor, and full professor. School teachers are never called professors in English. )