Editing Ontology (information science) (section)

== Formal Ontology Components ==
{{Main|Ontology components}}
Contemporary ontologies share many structural similarities, regardless of the language in which they are expressed. Most ontologies describe individuals (instances), classes (concepts), attributes and relations.

=== Types ===
==== Domain ontology<!--linked from 'Domain ontology'--> ====
A domain ontology (or domain-specific ontology) represents concepts which belong to a realm of the world, such as biology or politics. Each domain ontology typically models domain-specific definitions of terms. For example, the word ''[[:wikt:card|card]]'' has many different meanings. An ontology about the domain of [[poker]] would model the "[[playing card]]" meaning of the word, while an ontology about the domain of [[computer hardware]] would model the "[[punched card]]" and "[[video card]]" meanings.

Since domain ontologies are written by different people, they represent concepts in very specific and unique ways, and are often incompatible within the same project. As systems that rely on domain ontologies expand, they often need to merge domain ontologies by hand-tuning each entity or using a combination of software merging and hand-tuning. This presents a challenge to the ontology designer. Different ontologies in the same domain arise due to different languages, different intended usage of the ontologies, and different perceptions of the domain (based on cultural background, education, ideology, etc.){{citation needed|date=February 2021}}.

At present, merging ontologies that are not developed from a common [[upper ontology]] is a largely manual process and therefore time-consuming and expensive. Domain ontologies that use the same upper ontology to provide a set of basic elements with which to specify the meanings of the domain ontology entities can be merged with less effort. There are studies on generalized techniques for merging ontologies,<ref name="Dynamic Ontology Repair">{{cite web |url=http://dream.inf.ed.ac.uk/projects/dor/ |title=Project: Dynamic Ontology Repair |publisher= University of Edinburgh Department of Informatics|access-date=2 January 2012}}</ref> but this area of research is still ongoing, and it is a recent event to see the issue sidestepped by having multiple domain ontologies using the same upper ontology like the [[OBO Foundry]].

=== Upper ontology ===
{{Main|Upper ontology}}
An upper ontology (or foundation ontology) is a model of the commonly shared relations and objects that are generally applicable across a wide range of domain ontologies. It usually employs a [[core glossary]] that overarches the terms and associated object descriptions as they are used in various relevant domain ontologies.

Standardized upper ontologies available for use include [[Basic Formal Ontology|BFO]], [[BORO method]], [[Dublin Core]], [[General Formal Ontology|GFO]], [[Cyc]], [[Suggested Upper Merged Ontology|SUMO]], [[UMBEL]], and [[Upper ontology#DOLCE|DOLCE]].<ref name="DOLCE">{{cite web |url=http://www.loa-cnr.it/DOLCE.html |title=Laboratory for Applied Ontology - DOLCE |publisher=Laboratory for Applied Ontology (LOA)|access-date=10 February 2011}}</ref><ref name="DOLCE-OWL">{{cite web |url=http://www.ontologydesignpatterns.org/ont/dul/DUL.owl |title=OWL version of DOLCE+DnS  |publisher=Semantic Technology Lab|access-date=21 February 2013}}</ref> [[WordNet]] has been considered an upper ontology by some and has been used as a linguistic tool for learning domain ontologies.<ref>{{cite journal |first1=Roberto |last1=Navigli  |first2=Paola |last2=Velardi |year=2004 |title=Learning Domain Ontologies from Document Warehouses and Dedicated Web Sites |journal=[[Computational Linguistics (journal)|Computational Linguistics]] |volume=30 |issue=2 |publisher=MIT Press |pages=151–179 |doi=10.1162/089120104323093276|citeseerx=10.1.1.329.6965 |s2cid=2453822 }}</ref>

=== Hybrid ontology ===
The [[Gellish]] ontology is an example of a combination of an upper and a domain ontology.