Ontology (information science) — Wikipedia
Neutral reference on what an ontology is in computer/information science, grounding the ontology page beyond the single practitioner essay it had drawn on.
What it establishes
- Gruber’s classic definition (1993): an ontology is “a description (like a formal specification of a program) of the concepts and relationships that can formally exist for an agent or a community of agents” — the much-cited shorthand being “a specification of a conceptualization.”
- The axiom test (ontology vs. taxonomy): what separates a true ontology from a mere taxonomy is that it has “axioms that do constrain the possible interpretations for the defined terms” — not just a naming hierarchy. Gruber: “ontologies need not be limited to” taxonomic hierarchies and the subsumption relation.
- Components: contemporary ontologies describe individuals (instances), classes (concepts), attributes (properties), and relations between entities — plus restrictions, rules, and axioms.
- Languages/standards: OWL (Web Ontology Language, built on RDF/RDFS for the Semantic Web), RDF/RDFS as the foundation, and CycL (the Cyc project’s language, based on first-order predicate calculus).
- Domain vs. upper ontologies: domain ontologies model one area (biology, finance) and are often mutually incompatible without a shared foundation; upper/foundation ontologies supply commonly-applicable objects and relations across domains for interoperability.
Tier
T2 — Wikipedia, a neutral encyclopedic source for an established, decades-old technical concept.