Technical debt utilises financial debt as a metaphor to describe the phenomenon of increasing software development costs over time. Whilst this phenomenon is evidently detrimental to the long-term success of software development, it appears to be poorly understood in the academic literature. The absence of a clear definition and model for technical debt means that the notion of technical debt remains metaphorical, thus preventing the realisation of technical debt's utility as a conceptual and technical communication device. This exploratory study reconciles the high-level, abstracted view of technical debt presented in academic literature. It establishes the boundaries of the technical debt phenomenon and develops a comprehensive theoretical framework to facilitate future research. The resulting theoretical framework portrays a holistic view of technical debt that incorporates a set of precedents and outcomes, as well as the phenomenon itself.