Second screening is a widespread activity among users, although many are not aware of the term, and second screen applications are becoming increasingly popular in research and commercial use, from well-known examples such as Netflix, Amazon Prime Video or YouTube to applications that enable novel uses cases and have the potential to change the current usage behavior of the content on the first screen. Despite the increasing prevalence of this phenomenon, there are different interpretations in the relevant literature and in existing applications about what exactly is meant by the term second screen. In order to evaluate these different interpretations, we conducted a structured review of literature (SRL) on 65 publications in this area and reflected the results on an analysis of currently available second screen applications to precisely delineate the term and its characteristics. Furthermore, we derived a content and technical classification that will make it easier to manage the various benefits and characteristics of second screen applications in the future, to create a framework for the appropriate positioning of new research activities and reasoned basis for discussion.