OSID Specifications
ontology package
Version 3.0.0
Release Candidate Preview
TitleOntology Open Service Interface Definitions

The Ontology OSID is an auxiliary service used to define subject matter that can be related to OsidObjects. Ontologies are an alternative to tagging where structure, restricted vocabulary, or localization of topic names are desired.


Subjects are used to represent a topic and can be organized in a hierarchy to form an ontology.


Subjects are related to OSID Ids with a Relevancy. A Relevancy is an OsidRelationship.

Ontology Cataloging

Subjects and Relevancies are organized into Ontology catalogs.

An external Id may be mapped to an Ontology. This mapping allows OsidCatalogs to relate to a specific and sharable Ontology to constrain a set of Subjects that may be relevant to a collection of external OsidObjects.

Sub Packages

The Ontology OSID includes a rules subpackage for managing rules to enable subject relevancies and an Ontology Batch OSID for managing Subjects, Relevancies, and Ontologies in bulk.