Based on the literature review, this paper defines and discusses "overwork" in the following three aspects: its labor performance, health symptoms, and adverse consequences. The interpretations of the word, by combining the above three definitions together, highlight not only their causations, but also their differential layers of depth in analyzing the notion. Moreover, this study also puts forward, in addition to the notion of overwork in both its broad sense and narrow sense alike, detailed interpretations on other confusing vocabulary concerned with the notion. Thus, the connotations and denotations of the notion of overwork, based on its classified interpretations and different features, can be clarified.