Editing Web Ontology Language (section)

===Relation to description logics===
OWL classes correspond to [[description logic]] (DL) ''concepts'', OWL properties to DL ''roles'', while ''individuals'' are called the same way in both the OWL and the DL terminology.<ref>{{cite book |last=Sikos |first=Leslie F. |date=2017 |title=Description Logics in Multimedia Reasoning |url=https://www.springer.com/us/book/9783319540658 |location=Cham |publisher=Springer International Publishing |isbn=978-3-319-54066-5 |doi=10.1007/978-3-319-54066-5 |s2cid=3180114 }}</ref>

{{blockquote|In the beginning, IS-A was quite simple. Today, however, there are almost as many meanings for this inheritance link as there are knowledge-representation systems.|[[Ronald J. Brachman]]|''What IS-A is and isn't''<ref>Brachman, Ronald J. (1983); ''What IS-A is and isn't: An analysis of taxonomic links in semantic networks'', IEEE Computer, vol. 16, no. 10, pp. 30-36</ref>}}

Early attempts to build large ontologies were plagued by a lack of clear definitions. Members of the OWL family have [[model theory|model theoretic]] formal semantics, and so have strong [[logic]]al foundations.

Description logics are a family of logics that are decidable fragments of [[first-order logic]] with attractive and well-understood computational properties. OWL DL and OWL Lite semantics are based on DLs.<ref>{{cite web |url=http://www.cs.man.ac.uk/~horrocks/Publications/download/2003/HoPa03c.pdf |first1=Ian |last1=Horrocks |first2=Peter F. |last2=Patel-Schneider |title=Reducing OWL Entailment to Description Logic Satisfiability }}</ref>
They combine a syntax for describing and exchanging ontologies, and formal semantics that gives them meaning. For example, OWL DL corresponds to the <math>\mathcal{SHOIN}^\mathcal{(D)}</math> description logic, while OWL 2 corresponds to the <math>\mathcal{SROIQ}^\mathcal{(D)}</math> logic.<ref>{{cite book |title=Foundations of Semantic Web Technologies |first1=Pascal |last1=Hitzler  |author-link1=Pascal Hitzler |first2=Markus |last2=Krötzsch |first3=Sebastian |last3=Rudolph |publisher=CRCPress |date=2009-08-25 |isbn=978-1-4200-9050-5 |url=http://www.semantic-web-book.org }}</ref> Sound, complete, terminating [[reasoner]]s (i.e. systems which are guaranteed to derive every consequence of the knowledge in an ontology) exist for these DLs.