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.-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.