Usability in general and web usability in particular are complex concepts with multiple dimensions and elements/attributes. What is more, there is no comprehensive definition that takes into account the varying aspects of usability. This leads to discrepancies in policies/standards/guidelines which facilitate good usability practices. To initially address this problem, we took the first step of systematically analyzing the terms represented in formally published definitions from a number of sources in the subject areas of library & information science and computer science/information systems. Our results reveal that there are approximately 11 elements/attributes of usability and web usability addressed within these sources. The top five attributes are: learnability, effectiveness, user-related attributes, users' attitude/satisfaction, and efficiency. However, other critical usability attributes received little to no attention in publications of either discipline.