Ontology is a central area of metaphysics that examines what it means for something to exist and how different kinds of existence may be classified. Ontological questions ask what kinds of things are real, whether entities such as minds, numbers, properties, events, or abstract concepts exist in the same sense as physical objects, and how categories of being relate to one another. Ontology provides a framework for discussing existence, identity, substance, properties, relations, and categories of reality, and it often serves as a foundation for broader metaphysical inquiry.