<p>It is crucial in engineering that a device or system retains its functioning conditions when needed. However, sometimes devices and systems fail, stopping functioning at a satisfactory level, and becoming malfunctioning. Therefore, the study of malfunctions and their prevention is a core subject in engineering. Since this domain offers challenges, such as terminological and semantic heterogeneity issues, that can be addressed by applied ontology, in this work we focus on gaining an ontological understanding of engineering concepts related to malfunctions, producing a formal taxonomy that can help make relevant engineering knowledge semantically interoperable. (The taxonomy is also made openly available on an online repository.) In this context, causation is an especially relevant and interesting topic, and it is therefore the main focus of our analysis, with the help of a pre-existing ontology of causation. Our approach, which we also map and compare with other works in the literature, facilitates the ontological understanding and modeling of real-world failure cases, exploring the capabilities of failure analysis.</p>