Due to technological advances, IT is increasingly introduced and managed outside of (or even hidden from) an organization's IT department. Researchers and practitioners have created multiple concepts describing different facets and trends of this development. While the individual concepts typically focus on different aspects, there are overlaps between these concepts. This effect hampers research progress as it creates redundancies and separate streams of knowledge development. To close this gap, we propose a taxonomy of the concepts Lightweight IT, IT Consumerization, Bring Your Own Device, Shadow IT, and Business-Managed IT based on a structured literature review. For this purpose, we derive characterizing dimensions of each concept from existing studies and analyze literature according to the usage of terms. As a result, we can describe and delineate the concepts. Thus, we contribute a taxonomy of IT outside the IT department to improve the transfer of research results from between research streams.