Ontology is a branch of philosophy that deals with the study of the nature of being, existence, and reality. In the context of information science and knowledge management, ontology refers to a formal representation of knowledge within a specific domain. Ontologies are used to define the concepts, relationships, and properties that exist within a domain, allowing for the organization and categorization of information in a systematic and structured way. Ontologies are often used in areas such as artificial intelligence, information retrieval, and data integration to facilitate knowledge sharing and interoperability between different systems and applications.