Ontology

In information science it is used as model to describe a domain of knowledge with the help of classes, attributes, relationships and some more components. With the help of this domain of knowledge, the ontology is used as tool to create a common base of understanding on a topic. It can also be reused and extended.

After Gruber ontologies are an "explicit specification of a conceptualization".

Sources

1. Gruber, Thomas R.: Toward Principles for the Design of Ontologies Used for Knowledge Sharing. International Journal Human-Computer Studies 43(5-6):907-928, Elsevier, 1995.
2. https://www.w3.org/TR/2004/REC-owl-semantics-20040210/syntax.html