Metaphysics is the area of philosophy which deals with the ultimate nature of reality. Metaphysics can emcompass large areas of philosophy, and most other philosophical schools turn back to it for basic definition.
The term “metaphysics” comes from Greek, meaning “after the Physics”. Although the term metaphysics generally makes sense in the way that it partially refers to things outisde of and beyond the natural sciences, this is not the origin of the term (as opposted to, say, meta-ethics, which refers to the nature of ethics itself). Instead, the term was used by later editors of Aristotle. Aristotle had written several books on matter and physics, and followed those volumes with work on ontology, and other broad subjects. These editors referred to them as “the books that came after the books on physics” or “metaphysics”.
Aristotle himself refers to metaphysics as “first philosophy”. This term was also used by some later philosophers, such as Descartes, whose primary work on the subject of metaphysics is called Meditations on First Philosophy.
The main branches of metaphysics are: