| Upper ontology |
They are also called fundamental ontologies. In this type, there is a distinction between things that exist, such as objects, and things that happen, such as processes, and the ontologies are modeled better. |
| Domain ontology |
This kind of ontology(19) includes important topics of a particular domain, for example, for biology, physics or astronomy. |
| Reference ontology |
It is used for explicit display of the domain and usually created and developed without any specific application in mind. Reference ontologies are often used in high-level ontology to recognize the formal ontology of the domain. |
| Formal ontology |
Used for semantic coding based on logic. Therefore, computational or computerized inferences are made using automated reasoning. |
| Informal ontology |
It is the opposite of the formal ontologies. The informal ontology implies that the ontological diagnosis is not performed and the representation is done without the use of precise meanings. |
| Application ontology |
When the reference ontology provides explicit representation of an aspect of the domain, usually uses several reference ontologies to illustrate a particular applicable scenario. Also, additional information should often be added to the ontology to apply it. |
