Abstract
The paper defines a schema in which to describe the cornucopia applied ontologies. In contradistinction to the main trend in engineering meta-ontology the main ideas that support this schema are inspired by philosophy. Namely, we look at the domain of applied ontologies from the point of view of a certain metaphilosophical tradition. In a nutshell, we identify an applied ontology by means of (i) a description of its language, (ii) the employed methodology (if any), (iii) a description of sources of ontological knowledge used in its development (if any), (iv) a description of its domain, (v) the list of its categories (if any), and (vi) a description of its use (if any). The final result of our considerations is an engineering artefact, i.e., an OWL ontology. For the sake of validation we employ it to describe several applied ontologies of diverse kinds.