The distinction between reference ontologies and application ontologies crept rather unobtrusively into the recent literature on knowledge engineering. A lot of the discourse surrounding this distinction – notably, the one framing the workshop generating this collection of papers – suggests the two types of ontologies are in some sort of opposition to one another. Thus, Borge et al.  characterize reference ontologies (more recently, foundational ontologies) as rich, axiomatic theories whose focus is to clarify the intended meanings of terms used in speciﬁc domains. Application ontologies, by contrast, provide a minimal terminological structure to ﬁt the needs of a speciﬁc community. Reﬂecting their minimal nature, Masolo et al.  refer to such ontologies as “lightweight” ontologies. An application ontology can be lightweight in a second respect as well, namely, that it may not necessarily take the form of fully-ﬂedged axiomatic theory. Rather, it might only be a taxonomy of the relevant domain, a division of the domain into a salient collection of classes, perhaps ordered by the subclass relation. Importantly, though, for an application ontology to “ﬁt the needs of a speciﬁc community” needn’t require representational accuracy. In the “worst” case (from a reference ontology perspective), to ﬁt the needs of a community is just to represent uncritically what people in that community think about the ontology’s domain.