A number of concepts related to human performance, such as occupation, purposeful activity, function, work, doing, and play/leisure, are widely used in occupational therapy. Because these concepts are essential to the profession, we seek to understand their meaning. Many theorists in occupational therapy define and attribute different levels of importance to each of these concepts. The present study examines the professional (student vs. practitioner) and universal (American vs. Israeli) meanings of the six concepts named above. Four statistical methods were used: (a) a multivariate analysis of variance, (b) t tests and a sign test to analyze the Osgood semantic differential, and (c) Individual Differences in Multidimensional Scaling (Carroll & Chang, 1970). The results indicate that the American occupational therapists ascribed higher affective meanings than did all of the other groups to the concepts of purposeful activity, function, doing, and work. No difference was found for occupation and hobby, which rated high for all groups. Differences in the dimensions underlying the concepts between American and Israeli subjects suggest a cultural and linguistic influence on the meaning ascribed to the concepts.