Ontology is a branch of philosophy that studies the nature of being, existence, and reality. It seeks to answer fundamental questions about what entities exist and how they can be categorized and related within a hierarchy. Ontologists explore concepts such as objects, properties, and relations to understand the structure of reality. In addition to its philosophical roots, ontology has practical applications in fields like computer science and information science, where it helps in organizing and structuring knowledge. By creating formal representations of concepts and their relationships, ontologies facilitate better data sharing and interoperability across systems.