Frequently asked questions
Short answers to the questions people ask most often about the Common Core Ontologies.
What does mid-level mean?
A mid-level ontology sits between a domain-neutral top-level ontology and the specialised terms of a single field. It is general enough to be shared across domains yet concrete enough to be useful, which is exactly the niche the Common Core Ontologies fill.
How is CCO related to BFO?
The Common Core Ontologies extend Basic Formal Ontology, the ISO/IEC 21838 top-level standard. Every CCO class refines a BFO category, so the suite inherits BFO's distinctions between continuants, occurrents, qualities and functions.
How many ontologies are in the suite?
Eleven, covering agents, artifacts, events, facilities, geospatial regions, information entities, qualities, time, units of measure, currency units and the extended relations that connect them.
Can I import just one ontology?
Yes. You can depend on a single module, such as the Information Entity Ontology, to keep the reasoning footprint small, or import the merged AllCoreOntology module to bring in the whole suite at one aligned release.
Is it free to use?
The suite is open and released under a permissive licence, so you can use and extend it in your own projects.
How should I extend it for my domain?
Add your terms as subclasses of the relevant CCO classes rather than redefining them. That way your ontology inherits the definitions above it and continues to line up with the suite as it is updated.