Ontology (Relational Vocabulary)

Definition of an Ontology

A type of relational controlled vocabularyA managed list of terms. In the context of vocabularies, management typically includes careful selection of terms, maintenance of terms over time (i.e. addition, deprecation, modification), and presentation of the vocabulary in an accessible format. Related Guide, which provides for categories, relationshipsConnections between metadata terms within a vocabulary. These relationships can connect terms by scope, provenance, or other well-defined criteria., rulesIn the context of crosswalking, rules are a process which define how to deal consistently with complex element mappings. Rules are created and applied during the mapping of elements from the source schema to the target schema, when one-to-one relationships between schema elements do not exist. Related Guide and axioms among metadata elementsIndividual instance of a metadata label and value pair. For example, "creator: John Doe" is a metadata element. Related Guide. Typically a hierarchy of classesGrouping of metadata values, based on shared criteria. Related Guide and terms, an ontology is a machine-readableIn the context of metadata, formatted in a way that is well defined and processable by the system's software and hardware. Metadata with this characteristic can be discovered, ingested, and presented by an electronic system (also known as 'computable'). Related Guide way of relating metadataData about data. Metadata provides a context for research findings, ideally in a machine-readable format. It enables discovery of data via an electronic interface, and correct use and attribution of findings. Related Guide terminology.

Discussion

Ontologies are, by far, the most complex type of vocabulary. By definition, ontologies include Multi-Level VocabulariesA managed list of metadata terms, where the terms are organized into categories. Multi-Level vocabularies include taxonomies and subject headings. Related Guide, relationships, rules and axioms. They enable the assignment of properties, comparisons using the complete list of relationships, and derived conclusions, based on established rules.

Due to the complexity of ontologies, more complete guidance documents have been developed.
For more information, please visit the Ontologies section.