Ontology (Relational Vocabulary)

Definition, description and example of a semantic network

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Definition of Ontology

A type of relational controlled vocabulary that provides for categories, relationships, rules and axioms among metadata elements. Typically a hierarchy of classes and terms, an ontology is a machine-readable way of relating metadata terminology.


Ontologies are, by far, the most complex type of vocabulary. By definition, ontologies include multilevel vocabularies, relationships, rules and axioms. They enable the assignment of properties, comparisons using the complete list of relationships, and derived conclusions based on established rules.

For more information, please visit the Ontologies section.

Suggested Citation

Neiswender, C. 2011. "Ontology (Relational Vocabulary)." In The MMI Guides: Navigating the World of Marine Metadata. http://marinemetadata.org/guides/vocabs/voctypes/voccat/ontology. Accessed August 14, 2020.