entityconcepts

Entity concepts refer to the formal and informal notions used to describe things that can be distinguished as separate entities within knowledge representations. In information science and artificial intelligence, an entity is any object, person, event, concept, or place that can be identified and discussed. Entity concepts function as the classes or types that group related entities; individuals instantiate these concepts. The term is commonly written as two words, but some schemas and databases may use concatenated forms such as entityconcepts as identifiers.

In ontologies and knowledge graphs, entity concepts are often represented as classes or types. An entity concept has a set of properties (attributes) and can participate in relations to other concepts. Distinctions are made between the concepts themselves (the types) and the instances that fill those concepts. For example, the entity concept Person might include properties such as name and date of birth, while a specific person such as "Ada Lovelace" is an instance.

Types of entity concepts can be physical (car, planet), digital (file, webpage), abstract (idea, value), or social (organization, role). Many schemas and standards use URIs to identify both concepts and instances; OWL and RDF provide mechanisms for defining class hierarchies, disjointness, and property constraints.

Common applications include enabling data integration across sources, supporting semantic search, and providing a foundation for automated reasoning. Challenges include disambiguation of homonyms, managing identity across systems, versioning of concepts, and balancing expressivity with computational tractability.

See also ontology, knowledge graph, concept, class, and entity resolution.