The study of systems-of-systems is an increasingly important topic in systems engineering. Though there is not complete agreement, a more precise definition of what these highly evolved systems are and what attributes they possess has certainly emerged. However, there are still areas in the study where the topic can be advanced by a more rigorous presentation of the basic elements. One such area is the taxonomy of systems-ofsystems. This paper will begin with the definition of systems-of-systems as it currently stands and will present the taxonomy from a broader view with additional considerations for classification. These taxonomic categories will consider dimensions in the classification of systems-ofsystems based on their acquisition strategy, operational mode, and problem domain with examples in each case.