An ontology is a structured framework that helps organize and categorize knowledge within a specific domain. It defines the concepts, relationships, and properties of the entities involved, allowing for a shared understanding of the subject matter. For example, in the field of biology, an ontology might outline the relationships between different species, their characteristics, and their habitats. Ontologies are widely used in various fields, including computer science, artificial intelligence, and information science. They facilitate data sharing and integration by providing a common vocabulary and structure, making it easier for systems and people to communicate and understand complex information.