The definition of 'medical humanities' may be approached via three conceptions-the humanities as a list of disciplines, as a program of moral development, and as a supportive friend. The conceptions are grounded by linking them to three narratives-respectively, the history of the modern liberal arts college; the history of Petrarch and the studia humanitatis of the early Renaissance; and the life of Sir William Osler. The three conceptions are complementary, each filling gaps in one or more of the others. Getting clearer on a definition of 'medical humanities' is practically important if this field is to take its rightful place within health professions education and practice.