Since emerging in academic literature in the 1990s, definitions of ‘cyber war’ and cyber warfare’ have been notably inconsistent. There has been no research that examines these inconsistencies and whether they can be resolved. Using the methodology of discourse analysis, this thesis addresses this research need. Analysis has identified that the study of cyber war and cyber warfare is inherently interdisciplinary. The most prominent academic disciplines contributing definitions are Strategic Studies, Security Studies, Information and Communications Technology, Law, and Military Studies. Despite the apparent definitional uncertainty, most researchers do not offer formal definitions of cyber war or cyber warfare. Moreover, there is little evidentiary basis in literature to distinguish between cyber war and cyber warfare. Proximate analysis of definitions of cyber war and cyber warfare suggests a high level of inconsistency between dozens of definitions. However, through deeper analysis of both the relationships between definitions and their underlying structure, this thesis demonstrates that (a) the relationships between definitions can be represented hierarchically, through a discourse hierarchy of definitions; and (b) all definitions share a common underlying structure, accessible through the application of a structural definition model. Crucially, analysis of definitions via these constructs allows a foundational definition of cyber war and cyber warfare to be identified. Concomitantly, use of the model identifies the areas of greatest interdefinitional inconsistency and the implications thereof and contributes to the construction of a taxonomy of definitions of cyber war and cyber warfare. Considered holistically, these research outputs allow for significant resolution of the inconsistency between definitions. Moreover, these outputs provide a basis for the emergence of dominant functional definitions that may aid in the development of policy, strategy, and doctrine.