From Longman Dictionary of Contemporary Englishassistant professorasˌsistant proˈfessor noun [countable] SECthe lowest rank of professor at an American university
Examples from the Corpus
assistant professor• He got his Nobel for the work he started as an assistant professor at Harvard.• On I January 1803 he was appointed assistant professor at 100 guineas perannum.• She joined the faculty of the nursing school at UC-San Francisco in 1957 and served as assistant professor until 1969.• Coleman seems to have been rather silently supported by Sewell as assistant professor. 