Two teachers gathered psychology definitions from 1,000 college students enrolled in introductory psychology classes on the first and last days of class during two successive fall terms at the University of Tennessee. A word analysis of first-day definitions suggested three major themes: behavior, mind/brain, and environment. These terms showed that the conventional wisdom of these students about how psychology is defined remained consistent, in most ways, with actual textbook definitions. Last-day definitions revealed very close agreement with definitions contained in the text and used by the teacher in the introductory psychology class. Introductory textbook authors and teachers of introductory classes should understand prevailing, conventional definitions of psychology and be aware of the influence a textbook definition and the definition teachers use in class have on the students' view of psychology. (Author)